Eur J Cardiothorac Surg 2006;29:S251-S258
© 2006 Elsevier Science NL
Left ventricular geometry reconstruction in ischemic cardiomyopathy patients with predominantly hypokinetic left ventricle
Leo A. Bockeria
a
,
Alexandr J. Gorodkov
a
,
Alexey V. Dorofeev
a
,
Michael D. Alshibaya
a
,
*
, the RESTORE Group
a Bakoulev Scientific Center for Cardiovascular Surgery, Moscow, Russia
Received 2 February 2006;
accepted 8 February 2006.
* Corresponding author. Address: Bakoulev Center for Cardiovascular Surgery, 135 Roublevskoye Shosse, Moscow, Russia, 121552. Tel.: +7 095 978 0645. (Email: alshibaya{at}mail.ru).
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Abstract
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Objective: The effectiveness of the left ventricle (LV) geometry reconstruction (Dor procedure) as the method of surgical treatment of LV post-infarction aneurysm and large dilated myocardial scars is well established. The efficacy of LV restoration in cases of globally dilated hypofunctional LV, containing the same spherical architecture as scarred, remains questionable. Methods: The results of LV geometry reconstruction in small population of patients with ischemic dilated cardiomyopathy (IDCMP) and predominantly hypokinetic LV are described in 14 patients of that underwent LV rebuilding into a conical architecture. Surgical procedures included LV geometry reconstruction with the synthetic patch, narrowing of widened dimensions between papillary muscles, coronary artery bypass grafting (CABG) and, in several cases, mitral and tricuspid valves annuloplasty. Results: Initial mean end-diastolic and end-systolic volumes indexes were 177 and 112 ml/m2, respectively, mean LV ejection fraction (EF) of 32.9%. The analysis of immediate and mid-term (1 and 4 years) results proved that LV reconstruction markedly decreased LV volumes and increased LVEF an average of +12% above resting values with significant improvement in clinical status. Conclusions: A rebuilding procedure for the scarred heart is now introduced to be used in ischemic patients with dilated ischemic cardiomyopathy without significant scar. Preliminary structural and physiological results imply that creating an elliptical form has potential importance during LV reconstruction of very sick patients with IDCMP without discrete scar.
Key Words: Congestive heart failure • Ischemic cardiomyopathy • Hypokinesia • Left ventricular reconstruction • Mitral regurgitation • Spiral flows
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1. Introduction
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The evolution of interest into geometric approaches to reduce volume in dilated cardiomyopathy (CMP) began with reports by Dor et al. [1] and Jatene [2], and this stimulus has introduced a broad series of contributions by many different surgeons and scientists [3–6]. In the beginning of XXI century, Buckberg [7] focused upon the conception of the linkage between helical anatomy and resultant cardiac function, a concept that was based upon macroscopic spatial considerations carried out by Torrent-Guasp and coworkers [8], when he introduced the ventricular myocardial band that defined cardiac configuration.
Buckberg, in discussing the helical heart, introduced the potential surgical solution of changing the spherical chamber of heart failure into an elliptical configuration. The concept addressed alteration of the ventricular form to restore a more normal geometry, with application toward a spectrum of diseases that ranged from ischemic to valvular to non-ischemic processes. The end result was creation of a conical chamber by placing a patch into the left ventricle between the apex (adjacent to the papillary muscle) and the high septum beneath the aorta. This procedure was termed Pacopexy [8], to honor the novel thinking introduced by Torrent-Guasp; others call this the SAVE (septal anterior ventricular exclusion) procedure [9].
The Bakoulev Scientific Center experience with LV reconstruction in dilated ischemic CMP proved this reconstruction concept, and moreover showed that LV rebuilding with a synthetic patch leads to the restoration of normal spiral blood flow in the left ventricular cavity [10]. LV surgical restoration was initiated in 1994 in patients with LV aneurysms, with subsequent progression of this technique to patients with predominant LV akinesis, until the current application toward ischemic heart disease (IHD) patients with dilated, hypokinetic LV without scar. The underlying concept was that ventricular form must be rebuilt in congestive heart failure patients with ischemic dilated CMP, and ventricular shape, rather than discrete scar, is the guideline to surgical intervention.
The overall experience with this form-related concept of surgical restoration has led to recent application in children with Bland–White–Garland syndrome, in patients with dilated non-ischemic CMP, and following of LV marked dilatation due to valvular heart disease. This report will only address results of the subset of 14 patients, amongst the total overall series of 244 ischemic cardiomyopathy patients that underwent LV geometry restoration with synthetic patch. In this cohort, the underlying diagnosis was a predominantly hypokinetic LV, without scar, thereby reflecting a novel reason for reconstruction, since the objective was not exclusion of scar, but rather rebuilding a more conical LV chamber form.
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2. Materials and methods
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2.1 Clinical status
Among 14 patients there were 11 men and 3 women; mean age was 51.4 ± 5.1 years. All patients were in NYHA classes III and IV (mean 3.5 ± 0.3), each had severe angina (mean 3.1 ± 0.6 Canadian Cardiovascular Society, CCS) class and some degree of pulmonary congestion. Nine patients suffered previous myocardial infarction. Mean cardiothoracic index was 0.54 ± 0.11. Eight patients (57%) required diuretics preoperatively. There was no electrocardiographic evidence of extensive myocardial scar: ECG changes usually consisted in R-wave reduction in the leads I, II, avL, V2-5 and sometimes in T-wave changes.
2.2 Coronary angiography and LV function
Mean number of diseased coronary vessels was 3.2 ± 1.1 per patient, and left main coronary artery disease was observed in four patients (29%). Mean LV end-diastolic volume index (EDVI) and LV end-systolic volume index (ESVI), measured by echocardiography was 177 ± 21 ml/m2 and 112 ± 19 ml/m2, respectively, and mean LV ejection fraction (EF) was 32.9 ± 5.4%. Pulmonary artery mean systolic and diastolic pressures were 38.4 ± 6.3 mmHg and 18.7 ± 4 mmHg, respectively. The sphericity and conicity indexes of LV [11] indicated significant LV spherical remodeling, as compared to normal, echocardiographic study showed increased mid and apical systolic sphericity (0.52 ± 0.01 to 0.6 ± 0.02*, and 0.32 ± 0.01 to 0.44 ± 0.01*) in each patient. Relative mitral insufficiency was evident, as 2+ regurgitation was observed in 11 patients, and 3+ mitral regurgitation occurred in 3 patients. Two patients also experienced more than 2+ tricuspid regurgitation.
2.3 Surgical technique and intraoperative management
Intraoperative monitoring included the measurement of arterial, central venous, and pulmonary artery pressure, cardiac index by Swan-Ganz catheter, LV volume and EF by transesophageal echocardiography (TEE), blood gases, electrolytes and intravenous diuresis. Preoperative intra aortic balloon counterpulsation was used in five patients (36%). Operations were performed under mild hypothermic (28 °C) cardiopulmonary bypass (CPB) with bicaval cannulation. After initiation of CPB and aortic cross-clamping, cardioplegia with Bretschneider solution (Kustodiol, 3.0 l) was administered into the aortic root (2000 ml) and via the coronary sinus (1000 ml).
The order of the procedure was to initially address the ventricle, then the coronary vessels, and finally the valve repair. The LV was opened 2 cm to the left and parallel to the anterior interventricular groove. An oblique purse-string suture was placed to include an upper region border of relatively normal muscle approximately 2–3 cm beneath the aortic valve on the septum that was adjacent to hypofunctional areas, and near the apex close to the papillary muscle in hypofunctional regions. The suture was slightly tightened to form a relatively narrow ‘neck’, and this represented a rim for patch placement. The synthetic oval-shaped patch was inserted, with its attachment to the formed ‘neck’ created by using a prolene 2/0 over and over suture to make this placement. The ventriculotomy was closed over the patch, by employing a linear two-layer prolene 2/0 suture, usually without the need for pledgets (Fig. 1
). CABG was then performed, with an average of 3.1 distal coronary anastomoses; the left internal mammary artery was used in all 14 patients. Mitral valve repair was performed in 3 patients, and tricuspid valve repair was done in 2 patients. Mean aortic cross-clamp time was 76 ± 21 min, and CPB time 121 ± 24 min.
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Fig. 1. Surgical technique: (1) opening of the LV; (2) purse-string suture at the border of relatively normal and hypofunctional zones; (3) synthetic patch implantation; (4) closure of ventriculotomy.
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3. Results
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3.1 Hemodynamics and contractility
Early hemodynamic studies showed that pulmonary artery wedge pressure (PAWP) fell from 18 ± 7 mmHg to 14 ± 5 mmHg and cardiac index (CI) rose from 2.3 ± 0.2 l/min m2 to 3.4 ± 0.4 l/min m2, and these improvements persisted throughout the 21-day hospitalization and follow-up interval. Perioperative echocardiographic study showed that restoration significantly decreased LVEDVI and LVESVI and increased LVEF an average of +12% above resting values. Besides from reducing ventricular volume, the procedure produces marked LV reshaping as shown by TEE studies (Fig. 2
).
3.2 Mortality and complications
Inotropic support in the postoperative period was necessary in eight patients (58%). Although intra aortic balloon counterpulsation (IABP) was used in six patients, five received IABP preoperatively, and one balloon was inserted for impaired hemodynamics during weaning from CPB. Cerebral complications were observed in two patients: one patient had embolic origin from clots present in the LV cavity, the other patient developed cerebral edema from circulatory hypoxia during CPB. Mean duration of stay in the intensive care unit was 3.9 days, and hospital stay was 21.4 ± 6.9 days. One patient died on 22nd postoperative day because low cardiac output led to development of multiple organ failure and sepsis.
3.3 Long-term results
The initial follow-up period was 1.4 years in the 13 patient survivors, with no late deaths. Two patients were re-hospitalized because of recurrent congestive heart failure, but there was no evidence of significant mitral or tricuspid regurgitation in the 13 patients during the follow-up interval. All but one patient was angina-free, although four patients continued to use diuretics. The mean NYHA functional class improved from 3.5 ± 0.3 to 1.4 ± 0.8.
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4. Discussion
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The anatomic features of a dilated heart following ischemic cardiomyopathy fall into three categories that are based upon the extent of scar formation and type of wall motion disorder. The majority have either dyskinetic aneurysm from extensive scar if there was no reperfusion, or develop a non-functional akinetic extensively scarred region due to either (a) early reperfusion with epicardial salvage, or (b) as a late finding following remote muscle dilation after early aneurysm formation [12]. The third category reflects a small group of IHD patients with significantly dilated poorly contracting left ventricle, but without massive scars; the involved muscle contains a thick hypofunctional hibernating myocardium, and is the subject of this report.
The term for this type is ‘predominantly hypokinetic LV’, and this global stretch likely derives from multiple small areas of infarction leading to progressive dilation. The main features of this pathologic entity include: (1) clinical signs of congestive heart failure (NYHA class 2 and more), (2) angiographic confirmation of severe coronary artery disease, (3) LV dilatation with EDVI > 100 ml/m2 and ESVI > 70 ml/m2, (4) LVEF of 35% and less, (5) relative mitral insufficiency (2+ and more) caused in most cases by the ‘restrictive’ mechanism, whereby there is structural widening between papillary muscles due to stretch and lateral displacements that results in excessive chordal tension and limited leaflet coaptation, (6) shape alteration due to marked LV spherical remodeling with the adverse of sphericity and conicity indices, and (7) thick myocardium, rather than scar at the apex and anterior wall. Although the global LV wall is predominantly hypokinetic, several patients exhibited a local, very limited, zone of LV akinesis from a small scar.
The concept to address LV reconstruction in these patients stemmed from prior clinical disappointment with the effects of myocardial revascularization alone in such patients. Our expectations that new blood supply would lead to the regression of left ventricular dysfunction, reversal of remodeling, and improved of late follow-up clinical status [13] was not always obtained. This tendency was greatest as ventricular volume progressively increased; late follow-up in some post-CABG patients with initial end-diastolic volume >250 ml demonstrated a further increase of volume and progression of heart failure rather than the expected improvement. This data led us to the idea applying the principles of the Dor procedure in hypokinetic hearts without extensive scar. The objective was the achievement of same structural reconstruction result to be achieved by rebuilding form, rather than focusing upon exclusion of scar.
Two basic surgical principles involving the papillary muscles and insuring an oblique ventricular closure were addressed as a modified Dor and coworkers [6] procedure of left ventricular reconstruction with synthetic patch was applied to these 14 patients. First, stitches comprising the purse-string suture on lateral ventricular wall must be situated at the bases of both widened papillary muscles, thereby bringing the papillary muscles closer together after tightening the purse-string suture. This simple maneuver was initiated in 2001, and often eliminates the so-called ‘restrictive’ mechanism [14] to improve relative mitral insufficiency [5]. Second, to achieve a conical chamber, an oblique position is used for placement of the purse-string suture that provides a rim for subsequent patch insertion. The anatomic guidelines are selecting a site on the high interventricular septum and anterior wall for the top of the patch, then carrying the suture more distally beneath the bases of papillary muscles on lateral and posterior walls of the left ventricle, thereby excluding a zone of myocardium that is significantly larger than the scar area (Fig. 3
). This purse-string suture serves as reference point to subsequent patch insertion. In some patients, the widening between the papillary muscles may be effectively narrowed with placing imbricating sutures between the papillary muscle bases, as recently described [5].
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Fig. 3. LV remodeling after patch implantation: (1) TEE before procedure—spherical form of LV; (2) TEE after reconstruction—conical form of LV; (3) purse-string suture to narrow the widened papillary muscle dimension; (4) oblique and correct position of the patch.
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At ventriculotomy, some degree of myocardial fibrosis was present in each of 14 patients. The range extended from significant fibrous layers to almost full absence of fibrous changes (Fig. 4
). In 3 patients, parietal clots were observed at the apex region, perhaps accounting for the embolus occurring in one patient. In patients with thick myocardium at the apex and anterior wall, microscopic examination revealed fine intramural fibrosis; a sharp contrast with histological findings observed in massive scars encountered with LV aneurysms.
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Fig. 4. Myocardial layers at the ventriculotomy show changes varying from minor intramyocardial fibrosis to significant fibrous scar.
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The functional counterpart to combining revascularization with reconstruction in patients with a thick myocardial layer in the apical and anterior LV wall is restoration of contractile capacity of the previously stretched hibernated area. In such cases, the healthy myocardium over the patch resumes its contractility. In one sense, the patch acts as a curtain, so that contraction of the more conically formed overlying muscle contributes to the mechanics of overall left ventricular contraction by ‘pushing or compressing’ the patch. This finding confirms the 1993 observations by Olearchyk and Sharif [15]. Evidence of such contributory patch movements was observed by TEE, EchoCG and color-kinetics, whereby the patch acts as an active endocardium so that no significant dysfunctional zone is evident on postoperative ventriculography (Fig. 5
). A final concert of clinical events follows this combination of myocardial revascularization and LV reconstruction, whereby there is rapid and significant reduction of LV volume, restoration of contractility, elimination of mitral insufficiency, and overall functional improvement.
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Fig. 5. Patch motion after reconstruction: (1) color-kinetics proves patch movement inside LV cavity during systole; (2) postoperative ventriculography: (a) diastole and (b) systole.
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While describing the helical heart, Buckberg [7] suggested the principles of golden section and a logarithmic spiral should also apply to the beating heart; this report suggests that perhaps the ‘ideal’ left ventricular ejection fraction should be 61.8%, a value developed by relating systolic and diastolic proportions to the ‘golden section’. The golden rule principle is not a unique observation, since the great ‘painter of spirals’ Leonardo da Vinci, in the 1500s, ingeniously guessed that the blood flow in the heart is spirally twirled. Furthermore, many other artists and scientists [16] have understood that spirals and the golden section are the fundamental harmonious landmarks upon which the Universe and our life are based (Fig. 6
).
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Fig. 6. Spirals in art: (1) the drawings of Leonardo da Vinci from Vindzore Library showing spiral flows in the heart cavity; (2) ‘spiral compositions’ of Russian painters: (a) V. Tatlin, (b) F. Infante, and (c) P. Belenock.
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In 1957, Torrent-Guasp created a new conception of functional anatomy of the heart by demonstrating how the myocardial band is spirally twisted. A prior functional counterpart was observed in 1974 at the Bakoulev Centre in Moscow, where Natalia Kuzmina's fundamental experimental studies precisely demonstrated that left ventricular flow patterns spirally twirled throughout the cardiac cycle [17]. Now there is strong evidence that the transmission of flow into the aorta is helically shaped [18]. Furthermore, Doppler-EchoCG imaging of the left ventricle in of healthy persons demonstrates that flow in the left ventricle also is helically twirled: half of the aorta and left ventricular cavity are painted in red and half—in dark blue proving spiral rotation of blood.
Consequently, spatial motion of flow in the LV and aorta on the normal person closely resembles patterns evident in typhoons or tornadoes. In contrast, there is destruction of helical flow that becomes lost in the dilated failing heart (Fig. 7
; ). However, correct implantation of an ‘oblique’ patch in dilated LV leads to the restoration of the spiral blood flow with the resumption of the double-colored LV cavity flow after restoration (Fig. 7; ).
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Fig. 7. The normal left ventricle has helical spiral flow within the left ventricular cavity. (7a) shows disruption of this normal helical spiral flow pattern in the ischemic dilated heart before surgical reconstruction. (7b) shows restoration of the normal helical spiral flow following patch implantation for restore left ventricular geometric configuration.
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Studies by Gorodkov, at the Bakoulev Scientific Center in Moscow have employed corrosion casts to document how the spiral architecture of the underlying muscular LV components compresses blood. The sections include plastic casts that define the LV cavity, and demonstrate (a) normal spiral trabecular orientation the healthy heart, (b) infringement of this spiral orientation by development more horizontal position of trabecules at dilated failing left ventricle, and (c) restoration toward the expected oblique orientation following LV restoration with an LV patch that allows subsequent surgical rebuilding of a more conical chamber that now contains spiral trabecular orientation (Fig. 8
). The spiral muscular patterns imprinted on cavity blood in (a) normal hearts, (b) following disease-related dilation, and (c) after repair closely abide by the changes in fiber orientation suggested previously [8], when the Torrent-Guasp model concepts were applied to normal, diseased and restored left ventricles.
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Fig. 8. Plastic casts of the left ventricle (A. Gorodkov): (1) normal; (2) dilated; (3) after patch reconstruction. Note the oblique spiral trabeculae in the normal heart (left), development of a more horizontal pattern in the dilated heart before ventricular restoration (center), and restoration of the natural spiral trabecular formation after patch placement to rebuild left ventricular geometry (right).
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5. Conclusions
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Left ventricular restoration with use of a synthetic patch combined with myocardial revascularization in patients with dilated ICMP secondary to ‘predominantly hypokinetic LV’ results in a highly effective surgical procedure. The consequences of reshaping of LV cavity toward a more elliptical chamber decrease ESV and EDV, PAWP and pulmonary congestion, increases EF and CI, and follow-up studies confirm a significant decrease of NYHA functional class and angina classification. The operative hypothesis is that this reconstruction procedure restores the normal helical configuration and resultant spiral blood flow within the LV cavity; a functional supposition that is the main reason for its hemodynamic efficacy. Form rather than scar exclusion is the objective. This is only a bias, as is learned from the well-known Russian painter Yuri Zlotnikov who said ‘everything that we do is only a working hypothesis’.
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Appendix A
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Supplementary data
Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.ejcts.2006.02.057
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Abstract
1. Introduction
