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a The Alfred Hospital, Melbourne, Australia
b St Vincent's Hospital, Sydney, Australia
c Royal Perth Hospital, Perth, Australia
d Papworth Hospital, Cambridge, United Kingdom
e Rikshospitalet, Oslo, Norway
f Auckland City Hospital, Auckland, New Zealand
g Prince Charles Hospital, Brisbane, Australia
h Ventracor Limited, Sydney, Australia
Received 13 March 2007; received in revised form 16 July 2007; accepted 17 July 2007.
* Corresponding author. Address: Ventracor Limited, 126 Greville Street, Chatswood, NSW 2067, Australia. Tel.: +61 2 9406 3102; fax: +61 2 9406 3111. (Email: john.woodard{at}ventracor.com).
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Abstract |
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 Top Abstract 1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Key Words: Assisted circulation • Heart-assist devices • Heart transplantation • Heart failure, congestive • VentrAssistTM
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1. Introduction |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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The ultimate aim of left ventricular assist device (LVAD) development has been to provide an alternative to heart transplantation by creating systems capable of circulatory support for an indefinite period [4]. However, this has been an elusive goal. Historically, the limited mechanical durability and unfavourable adverse event rates of early LVADs [2,4] have largely restricted their use to brief applications, such as ‘bridging’ transplant-eligible candidates until a suitable donor organ becomes available. The limitations associated with earlier LVADs and the requirement for further options for the aging heart failure population have catalysed the ongoing development of ‘next-generation’ LVADs.
The VentrAssistTM LVAD is one of the more recently developed LVADs; it has a third-generation, implantable, centrifugal blood pump with hydrodynamic suspension (Fig. 1 ) [5]. This LVAD has been designed for patients who potentially require long-term circulatory support. Conceived in 1998, with the first human use in June 2003 [5], the VentrAssistTM is now approved for use in Europe (‘CE Marked’).
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2. Methods |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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2.2 Surgical technique
The VentrAssistTM pump is typically implanted via a median sternotomy using conventional cardiopulmonary bypass. The pump is placed in a ‘pocket’ on the left side below the diaphragm, either in a pocket formed in the posterior rectus sheath or in a preperitoneal position behind the rectus. The diaphragm is reflected off the anterior chest wall to allow passage of the inflow and outflow cannulae.
Coring of the ventricular apex is generally performed using a supplied 16.5-mm diameter circular knife; some surgeons, however, prefer to make a freehand incision using scalpel and scissors. The 10 mm internal diameter silicone inflow cannula has a polyester felt flange that facilitates suturing to the apical myocardium. The ventricular anastomosis is completed using horizontal mattress sutures buttressed with Teflon pledgets. The outflow cannula is composed of a 10 mm gelatine-impregnated woven Dacron conduit with the first 18 cm covered by a fenestrated polypropylene tube that prevents kinking as the outflow traverses the epigastrium and pericardial space. The aortic anastomosis is completed in a standard end-to-side fashion.
The percutaneous lead is tunnelled through the subcutaneous fat to exit the body in the upper right quadrant. The lead is secured to the skin using adhesive patches and protected from infection with sterile dressings.
2.3 Clinical trial methods
For ethical and safety reasons, a pilot trial was conducted before the pivotal CE Mark trial commenced. The methods for these two completed clinical trials (Table 1
) are described below.
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The trial was approved by the Human Research Ethics Committee of The Alfred Hospital, and performed in accordance with the ethical principles of the Declaration of Helsinki.
Unconventionally, we decided to perform initial implants as DT in elderly non-transplant candidates. After four DT implants, and as confidence with the VentrAssistTM grew, a protocol amendment was approved permitting high-risk, transplant-eligible patients to be implanted as a BTT. The ‘high-risk’ patients were defined as those unlikely to receive an approved device for BTT due to age, with a smaller body (body surface area less than 1.7 m2) who may require a prolonged BTT (longer than 3 months) and who were suspected of having a ‘covert’ infection or requiring a BTT device when no suitable approved device was available. A minimal anticoagulation protocol was employed: warfarin to an international normalised ratio (INR) of 2.0–2.5 and acetylsalicylic acid at 100 mg/day. Intensive follow-up was performed for 12 months and then quarterly, or until heart transplantation.
2.3.2 CE Mark trial
This trial was a single-arm, multicentre, Phase II trial designed to support a CE Mark application. The primary objective was to establish the efficacy and safety of the VentrAssistTM system.
The trial was approved by the ethics committees of the seven participating institutions in Australia, New Zealand, Norway and the United Kingdom, and performed in accordance with the ethical principles of the Declaration of Helsinki.
Patients were eligible if they were deemed appropriate for heart transplant or were likely to become transplant-eligible following LVAD implant as per institutional rules. Patients were excluded if they suffered cardiogenic shock, acute myocardial infarction or cardiac arrest in the 48 h prior to enrolment; had primary right-sided heart failure confirmed by echocardiogram, with central venous pressure greater than 15 mmHg and pulmonary artery systolic pressure greater than 60 mmHg determined by Swan-Ganz catheter; had hypertrophic obstructive cardiomyopathy or restrictive cardiomyopathy determined by transthoracic echocardiogram; possessed a prosthetic valve (biografts excepted); had a greater-than-mild aortic regurgitation; had recurrent ventricular tachycardia or ventricular fibrillation; had pulmonary hypertension, chronic renal failure, chronic liver failure or severe chronic obstructive pulmonary disease; had either a stroke within 90 days prior to enrolment or a history of cerebral vascular disease with significant extra cranial stenosis; had active sepsis or a body surface area less than 1.4 m2.
Similar to the pilot trial, a minimal anticoagulation protocol was employed: warfarin to an INR of 2.0–2.5 and acetylsalicylic acid at 100 mg/day.
Patients were followed for 154 days following implant or until they received a heart transplant if less than 154 days. This endpoint duration was based upon the mean time to transplant at three of the trial centres. The primary outcome measure was survival until transplant or transplant-eligibility (as determined by local clinical guidelines) at post-implant day 154. Trial success was defined as (a) being transplant-eligible with the device implanted or (b) actually being transplanted at or before post-implant day 154.
Safety was assessed by the incidence and severity of adverse events, all-cause mortality and concomitant medication use. In addition, because of the known complications associated with LVADs, information regarding a number of protocol-defined, special interest, serious adverse events (SAEs) was noted. The special interest AEs were: device-related failure/malfunction, device-related infection, haemorrhage, thromboembolism, neurological dysfunction, right ventricular failure, organ dysfunction (including renal, hepatic and respiratory), haemolysis, arrhythmia, cardiac tamponade and psychiatric disorder. Neurological events were classified as ‘stroke’ if they were confirmed by computed tomography or the symptoms lasted more than 24 h. Event description, action taken, causality, device relationship and outcome of each SAE were recorded and adjudicated. Members of the adjudication committee, namely the participating investigators, were ‘blinded’ to the hospital where the events occurred and excluded from adjudicating events that occurred at their institution.
The trial design allowed statistical significance to be determined based on the results from 30 patients. The primary hypothesis tested was that the VentrAssistTM would achieve a success rate of greater than 65%. Due to the sample size, the charts of Mehta and Cain [12] were used to determine the actual number of patient successes required for a 65% success rate. At least 25 patient successes were required to achieve 65% or greater success rate. Survival data were evaluated using competing outcomes methods [13]. Kaplan–Meier survival analyses were not performed due to the inappropriateness of this technique for evaluating competing outcomes, particularly in small samples [14]. Safety data are presented both descriptively and as a rate per patient-month. As most adverse events with LVADs occur in the first 30 days after implantation, data are presented as rate per patient-month within the first 30 days after implantation and rate per patient-month greater than 30 days after implantation.
2.4 Clinical Development Plan
As of January 30th, 2007, the VentrAssistTM Clinical Development Plan comprises seven clinical trials: two are complete, three are ongoing and two are approaching initiation (Table 1). Conducted at sites worldwide, these trials will generate the data required for both European/Australian post-market surveillance requirements and to apply for regulatory approval of the VentrAssistTM in USA. The two completed trials have been described above and summaries of the remaining five trials are presented below.
2.4.1 DT trial
Contemporaneously with the CE Mark trial, a DT trial was initiated at six of the CE Mark trial sites. The primary objective is to generate additional data on the efficacy and safety of the VentrAssistTM for use in patients with end-stage heart failure requiring indefinite circulatory support. The primary endpoint is survival of 50% of implanted patients to 1 year and 25% to 2 years. Secondary endpoints are quality of life and functional class.
This trial is a single-arm, 15-patient, sequential, multicentre trial with all eligible patients offered the VentrAssistTM. Patients participate in the trial for 2 years; thereafter, they are followed for SAEs and date of death. Inclusion and exclusion criteria are similar to the REMATCH trial [6].
2.4.2 BRACE trial
The ‘Better Results and Cost Effectiveness’ trial is an open, non-randomised, case-controlled observational trial being conducted at centres in Europe. The BRACE trial is not an ‘intention-to-treat’ trial and the inclusion criterion is ‘need for mechanical left ventricular support’. For the first time, the BRACE study will allow the performance of LVAD therapy to be tested on a homogenous population for whom long-term LVAD therapy, LVAD removal following recovery or heart transplantation are equally valuable outcomes for the patient. The primary endpoint for the BRACE trial is actuarial survival at 2 years.
2.4.3 US BTT feasibility trial
The United States Food and Drug Administration (FDA) approved a 10-patient feasibility trial of the VentrAssistTM for the BTT indication. In late 2006, the FDA approved an extension to the feasibility trial to allow implantation in up to 30 patients (in total) at up to 10 centres.
2.4.4 US BTT pivotal trial
Following successful completion of the US BTT feasibility trial, the US BTT pivotal trial will commence. Data from the US feasibility and pivotal BTT trials will be consolidated to expedite the BTT submission to the FDA.
2.4.5 US DT pivotal trial
This prospective, randomised, controlled trial will use an innovative modular design. Data from this trial will be used in the DTT submission to the FDA.
2.4.6 Additional clinical experience – Australian special access scheme
Individual use of unapproved medical devices is permitted in Australia under the special access scheme (SAS). Under this scheme, 12 patients who did not qualify for the clinical trials or who required the VentrAssistTM following trial completion have been implanted with a VentrAssistTM. Detailed clinical data are not collected under the SAS, although SAE reporting is performed as required by Australian post-market surveillance requirements [Active Implantable Medical Devices (AIMD). 90/385/EEC Directive, Annex 2 Section 3.1, Annex 4 Section 3 and Annex 5 Section 3.1. http://europa.eu.int/eur-lex/en/consleg/main/1990/en_1990L0385_index.html].
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3. Results |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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All patients survived the implantation surgery; three DT and two BTT patients were discharged from the hospital at a median of 65 days (minimum 35 days, maximum 97 days). In two patients, anticoagulation was suspended to facilitate other surgical procedures.
The mean overall survival for the four DT patients was 16 months (minimum 2.4 months, maximum 32.1 months). There were three long-term DT survivors (32.1, 19 and 10.9 months of support). The fourth DT patient died 73 days after implantation, due to respiratory and cardiac arrest with secondary occult abdominal infection.
The BTT patients were implanted for an average of 4.7 months (minimum 0.9 months, maximum 16.7 months). Of the five BTT patients, one received a heart transplant at 3.9 months, one died at 0.9 months from cardiac arrest and two died at 0.9 and 16.7 months from multi-organ failure.
In the final BTT patient, the device was replaced 1.1 months post-implant when increased pump power was unexpectedly encountered. This event was due to a thin film of fibrin deposited on one blade of the pump rotor, associated with a septic, hypercoagulable state. The patient died of intracranial haemorrhage 2.6 months after the VentrAssistTM had been successfully replaced with an alternative LVAD.
The SAE profile revealed no embolic neurological events, minimal sepsis and acceptable device performance in difficult cases. Overall 30-day mortality was 22%. The trial accumulated a total of 7.3 patient-years of experience.
3.1.2 CE Mark trial: results summary
The results for patients who completed the trial by the database lock date (July 31st, 2006) were analysed for the CE Mark submission and a summary is presented below. Long-term follow-up data from patients in this trial are being collected and will be published separately.
3.1.3 Participants
Of 40 patients screened, a total of 30 patients had completed the trial by July 31st, 2006 (Fig. 4
). Patients were predominantly male and the mean age was 51 years, which is typical for the BTT population (Table 2
). All 30 patients survived the implantation procedure. Of these 30 patients, 21 were discharged from hospital after a mean duration of 43 days. Of these 21 patients, 6 were never readmitted during the study. The remaining 15 patients were readmitted a total of 32 times during the study, for a mean duration of 9 days (minimum 1 day, maximum 32 days) per readmission.
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High levels of haemodynamic support were recorded after implantation. The mean cardiac output on the day following implantation was 4.8 l/min, corresponding to a cardiac/pump index of 2.5 l/min/m2 (median 2.3 l/min/m2). These outputs were achieved at low pump speeds (approximately 2000 rpm).
3.1.5 Safety: serious adverse events and deaths
Of the 76 SAEs, 53 were classified as protocol-defined, device-related SAEs and 23 were classified as ‘other’ as they did not meet the predefined special interest SAE criteria.
The most common protocol-defined, device-related SAE was infection, with 16 events occurring in 11 patients (Table 3 ). Although cardiac tamponade occurred in nine patients, none of the reported tamponade events was deemed to be caused directly by the device. These events were judged as either technical bleeds (due to lack of haemostasis at surgery) or due to a coagulopathy. All of these tamponade events occurred in the first half of the trial. There were no protocol-defined, device-related SAEs related to hepatic dysfunction, respiratory dysfunction, arrhythmia and psychiatric disease.
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The causes of the 23 ‘other’ device-related SAEs were: ventricular/atrial thrombus that was not identified by computed tomography (n = 5), pericardial effusion that did not cause tamponade (n = 3), right heart failure where the central venous pressure was <20 mmHg (n = 1), haemolysis where the plasma-free haemoglobin was <0.2 g/l for at least two consecutive days (n = 3), infections that were related to a previously counted infection (n = 6), lethargy (n = 2), occlusion of the inflow cannula by cardiac trabeculae (n = 1), multi-organ failure (n = 1) and chest remaining open for an extended period (n = 1).
The four deaths in the trial were due to multi-organ failure (n = 1), cerebral haemorrhage (n = 1), haemodynamic instability with respiratory dysfunction and positive blood cultures (n = 1) and hypotension with an ischaemic bowel (n = 1). Investigators determined that only one death was device-related. This death actually resulted from accidental destruction of the percutaneous lead on the day of implantation; urgent device replacement was required and performed successfully. The patient died 148 days later following an embolic stroke, with recurrent methicillin-resistant staph aureus pneumonia complicating the attendant bulbar palsy.
3.1.6 Neurological events
Most (80%) patients did not experience a neurological SAE. Of the six patients who experienced ‘strokes’, two experienced haemorrhagic strokes and four experienced embolic strokes. Of the two patients with haemorrhagic strokes, one died from the event and the other died 29 days after the stroke due to haemodynamic instability/respiratory dysfunction, with positive blood cultures. Of the four embolic stroke patients, three have been transplanted (post-implant days 32, 52 and 325) and one patient is ongoing. The outcomes for these patients were: a complete recovery with no sensory or motor deficit (n
= 2); some focal neurological deficit but no sensory deficit (n
= 1); sensory deficit (touch) and no motor deficit (n
= 1). Most (83%) strokes occurred within the first 30 days following implantation. Strokes occurred at only four of the seven centres.
3.1.7 Renal and hepatic function
Measures of renal function (serum creatinine) and hepatic function (serum bilirubin) improved after implantation. At baseline, 53% of the trial success patients had a recorded history of renal impairment/failure, with a mean serum creatinine of 0.121 mmol/l (upper limit of the normal range). At the last visit, mean serum creatinine was reduced to 0.106 mmol/l, which was within normal limits. Similarly, at baseline, hepatic disorders were noted in 20% of the trial success patients, as indicated by a serum bilirubin concentration of 30 µmol/l (upper limit of the normal range = 20 µmol/l). At the trial endpoint, mean serum bilirubin for these patients decreased to 9 µmol/l, suggesting an improvement in organ function.
3.1.8 Concomitant medication
As expected, medication administration altered considerably following implantation. Use of all cardiac-related medications, except calcium channel antagonists, fell from baseline to last visit. As expected, the use of inotropes, digoxin, diuretics and vasopressors, which were being used before implantation to treat congestive heart failure, was reduced after implantation, commensurate with mechanical support of the circulation and unloading of the left ventricle. Antiarrhythmic and beta-blocker use declined slightly. Only four patients were being treated with inotropes at their last visit and these patients did not achieve trial success (three patients died and one patient was explanted).
3.2 Clinical Development Plan: summary of experience
Considerable progress has been made on the development and execution of the VentrAssistTM Clinical Development Plan (Table 1).
Indeed, the overall clinical experience with the VentrAssistTM now represents the largest experience of any third-generation centrifugal device worldwide. As of January 30th, 2007, 87 patients, who have been entered into clinical trial and clinical experience programmes at 14 centres worldwide, have been implanted successfully with a VentrAssistTM (Table 1). Collectively, these implants have yielded a cumulative support time of more than 43 patient-years and a maximum implant duration of 2.7 years. Of these 87 patients, 27 are ongoing (alive on device), 33 have been transplanted, 1 patient has recovered (device explant with native heart recovery) and 26 have died on the device. The mean support duration for ongoing device patients is 103 days (range 1–832), mean support duration for transplanted patients is 98 days (range 4–486), support duration for the patients with recovery is 377 days and mean support duration for patients who died on device is 49 days (range 2–977).
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4. Discussion |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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In the CE Mark trial, the primary efficacy outcome measure (survival until transplant or transplant-eligibility) was achieved by 83% of patients implanted with a VentrAssistTM. This result compares favourably with published reports of 65–70% of patients achieving survival to transplant success with other LVADs [13]. The success rate achieved with the VentrAssistTM in the multicentre CE Mark trial is particularly notable given that each centre had to progress through an inevitable ‘learning curve’. As an example of the ability for each centre to develop proficiency with the VentrAssistTM, tamponade events were confined to the first half of the study.
Morbidity and mortality association with anticoagulation management of patients with mechanical support continues to challenge clinicians. The anticoagulation prophylaxis regimen used in the completed trials was relatively simple; the INR was monitored and acetylsalicylic acid used empirically. The INR level was relatively modest, compared to that recommended for other devices [15,16]. Despite the low levels of anticoagulants used, perioperative bleeding was an issue in early patients, and two of the five deaths in the CE Mark trial were associated with bleeding. Paradoxically, some patients required surgery for non-LVAD related conditions following implant and anticoagulation was suspended, without incident, for periods of up to 1 week. This may indicate that the anticoagulation regimen could perhaps be tailored for individual patients and changing medical conditions, rather than the empirical level of anticoagulation thought to be ‘required’ for the LVAD.
The ultimate demand for LVADs is thought to be as a permanent form of mechanical assistance. The demand for permanent assistance reflects the mismatch between transplant organ availability and the increasing incidence of heart failure in the aging population, in both developed and developing countries, the increasing prevalence of risk factors for heart failure and the supply–demand imbalance in clinical heart transplantation [17]. In this respect, the results reported thus far after a relatively short follow-up period can only begin to indicate whether the VentrAssistTM is suitable for long-term use. However, the low linearised rate of SAEs after implant and the absence of mechanical failure auger well for longer implant durations. Confidence in the VentrAssistTM system has also been strengthened by the fact that none of the early patients in the pilot trial died as a result of device failure or malfunction and also by the successful outcomes in the home discharge cohort. The VentrAssistTM LVAD represents one of the new generation of smaller, potentially more reliable, ‘next-generation’ LVADs. These LVADs may make long-term circulatory assist available to a wider range of the heart failure population; particularly those who are non-transplant eligible or those with smaller body habitus. The ongoing and forthcoming clinical trials will provide more definitive data regarding the long-term therapeutic potential of the VentrAssistTM LVAD.
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5. Conclusion |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Appendix A |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Dr M. Pasic (Berlin, Germany): Thank you, Professor Esmore, for a nice presentation and really excellent results. When we see that 6-month survival is 83% after left ventricular assist device implantation, it's really excellent results.
What is the reason for these excellent results?
Dr Esmore: I think I showed from the inclusion data that all the patients were at that 2 l/m2 or below in regard to their cardiac index.
In the pilot trial, 33% of the patients were on balloon pumps, 2 were ventilated, 2 were on dialysis, of the 9 patients. In the bridge trial, 33% were on balloon pumps and 7% were actually on ECMO at the time of device implant. And all of them have had other procedures, either cardiological or open-heart surgery. So these were not a highly selected group of patients. They’re actually quite a complex, what we might call more ‘real world’ cohort of patients. They were not highly selected in the setting of taking a young bridge group, implanting for 50 or so days and transplanting them. That is not the current challenge to mechanical support devices. So that's why in the pilot trial we went straight to destination therapy and more complex bridge patients to challenge the device. In the CE mark bridge trial we moved towards the more conventional patient and then achieving recovery and the 83% successful bridge rate.
And a point I would also make is this is actually a multicentre trial. Some of the units have only done 3 cases ever of mechanical support and are still getting good results with the VentrAssist LVAD. That means the device is user friendly. I think the units themselves have shown experience in transplantation, et cetera, but not necessarily huge experience in VAD capabilities. But they have been able to actually add mechanical support to their clinical arm successfully with this device.
Dr Pasic: What should be done when you implant left ventricular assist device and you see the patient has right ventricular failure and needs mechanical support for the right ventricle, what should be done?
Dr Esmore: Well, I think we’re always mindful of that. The quoted figures are that around about 10% of patients will need an RVAD in volume displacement pumps. And it has been said by informed people the incidence might be twice as high with continuous flow pumps.
We basically adopt a protocol of using nitric oxide prophylactically. As soon as the patient is ready to come off, we will have nitric oxide(20–40 ppm)inhalation and wean that over a period of days.
I think bleeding is an important surrogate for potential right heart failure, and we have done much to minimize that with antifibrinolytics and hopefully good haemostasis.
So I think that the low RVAD deployment rate is a reflection of the device's capabilities, but also the fact that, as I said, despite this being a multicentre trial, each of the groups have been able to actually optimize right heart function and demonstrate right heart function (RHF) improvement to get the results reported. The overall 30-day mortality was 6%: a couple of patients who died were gravely ill at the time of implant, basically had significant inotropic support for the right side, but were not considered bad enough to be mechanically supported on the right side; they just didn’t get over that hill. Perhaps in retrospect they may have benefited from interim RVAD support. One of them developed, I think, mesenteric ischaemia. Another progressed to multi-organ failure and passed away at 30–40 days. But overall, the experience has been favourable. As I said, some of the units have Thoratec, Novacor and Heartmate-1 devices, pumps that are actually said to be easier to use in the setting of avoiding right heart support but with the VentrAssist they still achieved an acceptable incidence of RHF.
Dr J. Lahpor (Utrecht, The Netherlands): Very interesting device. You were mentioning that you had moderate thromboembolic rates. Can you elaborate more on that and tell us how many TIAs and strokes there were.
Dr Esmore: In the pivotal trial, I don’t think you have this curve here, but in 30 patients there were 4 events. Two of those were during the perioperative period. One patient woke up, he was fine for 24 h and had an event: he was dysarthric for some days, however that settled and he was successfully transplanted. Another patient had a complex early course and developed bleeding, went back to the theatre twice, developed low flows, intracavity thrombus in the L ventricle, and had that opened and evacuated. He had an embolic event, but no associated hemiplegia or hemiparesis, I think it was to the occipital lobe. He was successfully transplanted with no long-term deficit.
Another patient had an intracerebral bleed at day 21. The day before he said, ‘I haven’t felt this good for 2 years.’ And one of the other speakers have mentioned, it developed in the presence of what appears to been therapeutic anticoagulation.
And the only other documented event which I truly believe was embolic was a patient out at 148 days. He had an event producing bulbar palsy; he developed an issue with swallowing and clearing of sputum. The resultant aspiration and refractory MRSA pulmonary sepsis saw support withdrawn.
And even back in the pilot trial, which I’m not specifically reporting, these were 70-year-olds and there were only a couple of neurological events, 1 intracerebral bleed and 1 TIA over 7.5 years cumulative VentrAssist support. These patients on continuous flow support, would sit down at a year and a half out and crack jokes with you. And this was not a 48-year-old bridge on 50 days support, but elderly males on permanent support. In those patients the incidence of neurological events was minimal.
And, of course, any thromboembolic events don’t necessarily have to be caused by the LVAD. They can come from the native heart, from the aorta or attendant carotid or intracerebral disease. So cumulative events are very, very small in this high-risk elderly population.
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Acknowledgments |
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Footnotes |
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\#9734;\#9734; Dr John Woodard is the Chief Scientific Officer of Ventracor Limited. In addition to being clinical investigators, Drs Don Esmore and Steven Tsui are members of Ventracor's Scientific Advisory Board. In compliance with the uniform requirements for manuscripts, established by the International Committee of Medical Journal Editors, Ventracor did not impose any impediment, directly or indirectly, on the publication of the study's results. The authors acknowledge the independent medical writing assistance provided by ProScribe Medical Communications (www.proscribe.com.au) for the revised manuscript. ProScribe's services were funded by Ventracor and complied with international guidelines for good publication practice.
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References |
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TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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