Eur J Cardiothorac Surg 2007;31:845-850. doi:10.1016/j.ejcts.2007.02.005
Copyright © 2007, European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved
Primary triple valve surgery for advanced rheumatic heart disease in Mainland China: a single-center experience with 871 clinical cases
Qing-Qi Han,
Zhi-Yun Xu*,
Bao-Ren Zhang,
Liang-Jian Zou,
Jia-Hua Hao,
Sheng-Dong Huang
Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, People's Republic of China
Received 5 December 2006;
received in revised form 28 January 2007;
accepted 2 February 2007.
* Corresponding author. Address: Department of Cardiothoracic surgery, Changhai Hospital, 174 Changhai Road, Shanghai 200433, People's Republic of China. Tel.: +86 21 25072914; fax: +86 21 65490979. (Email: xuzhiyun{at}gmail.com).
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Abstract
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Background: Triple valve surgery (TVS) is still of choice for advanced rheumatic heart disease (RHD), which has been associated with reported poor early and late outcomes. We describe the short- and long-term results after TVS in last two decades in Mainland China. Methods: From January 1985 to January 2005, a total of 871 patients (217 men, 654 women), with mean age of 42 ± 11 years, underwent primary TVS for isolated advanced RHD. All patients received replacement procedures in mitral and aortic position (845 mechanical, 26 bioprosthetic), and 840 patients received repair procedures and the other 31 received replacement procedures in tricuspid position (9 mechanical, 22 bioprosthetic). Preoperative, perioperative, and postoperative data were retrospectively analyzed and risk factors affecting early and late survival were evaluated. Results: The 30-day hospital mortality was 8% (n
= 71). Presence of ascites, New York Heart Association (NYHA) class IV and lower left ventricular ejection fraction (LVEF) were identified as independent risk factors for hospital mortality. Overall long-term survival rate was 71% ± 3% at 5 years, and 59% ± 5% at 10 years. The cardiac survival rate was 75% ± 3% at 5 years and 63% ± 4% at 10 years. The event-free survival rate at 5 years and 10 years was 61% ± 6% and 41% ± 13%, respectively. Multivariate analysis revealed advanced age, NYHA class IV and lower LVEF were associated with increased late mortality. The freedom from thromboembolism and anticoagulation-related hemorrhage at 10 years was 90% ± 4% and 81% ± 5%, respectively. Of the 508 patients still alive, 376 (74%) were in NYHA class I and II. Conclusions: Primary TVS for advanced RHD appears to offer satisfactory short- and long-term results with excellent symptomatic improvement. Cardiac-related late mortality following TVS may be improved by early surgical treatment before NYHA class IV or deterioration of LVEF occurs.
Key Words: Triple valve surgery • Rheumatic heart disease • New York Heart Association functional class • Left ventricular ejection fraction • Anticoagulation
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1. Introduction
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Rheumatic heart disease (RHD) remains to be a significant health burden in Mainland China, especially in rural areas where a major part of people live in poverty. It has been estimated the prevalence of RHD in China is at least 10 times as high as that in industrialized societies [1]. It has long been known advanced RHD may affect multiple valves and undermine myocardial function severely. Despite improvements in myocardial protection and operative techniques, triple valve surgery (TVS) remains to be a clinical challenge, for such patients are usually at their late stage of disease, which make them vulnerable to operation. Furthermore, they are often subjected to long duration of cardiopulmonary bypass (CPB) and prolonged myocardial ischemia. Results of single and double valve surgery have been well defined by many groups and there are also few reports defining short- and long-term outcomes after TVS [2–7]. Different patients’ characteristics and underlying pathophysiology, and various surgical profiles, however, make them a heterogeneous group; in addition, the number of cases in those studies is relatively small and may not provide sufficient data for statistical analysis.
The current study describes the experience with 871 patients who underwent primary TVS for isolated advanced RHD at a single cardiac center in Mainland China in an attempt to define early and late clinical outcomes and analyze independent predictors of adverse results.
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2. Materials and methods
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In this study, TVS defines the patients who underwent aortic and mitral valve replacement combined with either tricuspid repair or replacement during the same surgical procedure. From January 1985 to January 2005, 1137 patients received primary TVS at the department of cardiothoracic surgery of Changhai Hospital, Second Military Medical University (Shanghai, China). Of them 189 who received concomitant procedures and 77 who received TVS due to other valvular diseases rather than RHD were excluded from the present study. The remaining 871 who underwent primary selective TVS for isolated RHD were included, whose clinical, operative and outcome data were collected and analyzed under the institutional review board approval.
2.1 Patient characteristics
There were 654 women (75%) and 217 men (25%) with mean age of 42 ± 11 years (range, 17–64 years). Of them 479 (55%) were < 45 years, of whom 72 (15%) were <25 years. The major preoperative characteristics of the population were presented in Table 1
. The majority of patients were in New York Heart Association (NYHA) functional class III or IV. The cause of valvular disease was exclusively rheumatic in origin. The clinical manifestations were mitral stenosis in 502 (58%), mitral regurgitation in 246 (28%), and mixed mitral disease in 123 (14%), aortic stenosis in 272 (31%), aortic regurgitation in 468 (54%), and mixed aortic disease in 131 (15%), tricuspid stenosis in 11 (1%), tricuspid regurgitation in 843 (97%), and mixed tricuspid disease in 17 (2%). Cardiac catheterization and angiocardiography were performed in all patients earlier in the series. In the last 15 years echocardiography had reduced the need for catheterization and angiocardiography in only selected cases.
2.2 Operative technique
All operations were performed by the same group of surgeons. In the last 15 years, intraoperative transesophageal echocardiography was performed in all patients to assess the extent and severity of valve disease and the quality of the replacement or repair postoperatively. All operations were carried out through a median sternotomy incision. CPB was performed under moderate hypothermia (28–32 °C), utilizing a bubble or membrane oxygenator. Myocardial protection was offered by instillation of modified St. Thomas’ Hospital solution through the coronary ostia, and repeated at 20–25 min. Improved protection of the ventricles was provided by topical hypothermia with saline ice slush. After excision of the aortic valve, the mitral valve was exposed through the trans-septal approach. The anterior leaflet was excised, with a portion of the posterior leaflet and its chordal attachment preserved whenever possible. The prosthesis was implanted using interrupted horizontal mattress sutures with felt pledgets. The mitral prostheses were oriented in the anti-anatomic position. If mitral annular reconstruction was needed in case of extensive calcification, it was performed with the utilization of autologous pericardium before implantation of the prosthesis. After the mitral procedure, the aortic prosthesis was sewn in place also with interrupted horizontal mattress sutures with felt pledgets. The aortic prostheses were implanted perpendicular to the ventricular septum. In case the aortic annulus failed to admit the prosthesis sufficiently large enough to prevent excess ventricular work, it was enlarged with a patch of pericardium. Finally, the tricuspid valve was corrected. Repair procedure (modified De Vega procedure, Kay procedure, and ring annuloplasty) was performed on an ischemic heart or under the beating heart, and replacement procedure was performed while the ascending aorta was cross-clamped. The tricuspid prostheses were oriented perpendicular to the septal leaflet. All patients received replacement procedure in mitral and aortic position (845 mechanical, 26 bioprosthetic), and 840 patients received repair procedure and the other 31 received replacement procedure in tricuspid position (9 mechanical, 22 bioprosthetic). The major operative data were listed in Table 2
. Choice of the prosthesis was determined on the basis of the patient's age, economic status, special request, and comorbid factors. The type of mechanical prostheses included St. Jude (St. Jude Medical Inc., Minneapolis, MN), Carbomedics (Carbomedics Inc., Austin, TX), ATS (ATS Medical Inc., Minneapolis, MN) and tilting-disc (made in our own country) valves. The bioprosthetic valve was exclusively Hancock II porcine heart valve (Medtronics Inc, Minneapolis, MN).
2.3 Anticoagulation
Anticoagulation was initiated with chronic warfarin sodium after chest tubes were removed. In the first decade of this study, prothrombin time (PT) was used to monitor anticoagulation with target range equals 1.5 times control value, and between the year 1995 and 2000, a transition occurred from PT to international normalized ratio (INR), and in the last 5 years, INR was recommended exclusively for anticoagulation. The anticoagulation was carried out and controlled by the cooperation of the surgical center, outpatient clinic and their home physicians. The target INR was 2.0–2.5 for aortic and mitral mechanical prostheses implantation with tricuspid repair or bioprosthesis replacement (2.2–2.7 for atrial fibrillation (AF) patients), 2.5–3.0 for triple mechanical prostheses replacement (2.7–3.2 for AF patients). When triple bioprostheses were implanted, anticoagulation was just recommended in the first 6 months postoperatively for those without AF. Low-dose aspirin was also added in the latter portion of the study.
2.4 Follow-up
Follow-up was achieved by yearly outpatient clinic visits for detailed physical examination combined with echocardiographic assessment, correspondence questionnaires, contacting with the referring physicians, and use of social workers for direct patient contact. Complications reported by patients were confirmed by contacting their physicians, or by referring to their hospital records. Twenty-eight patients were lost to follow-up, leaving a follow-up rate of 96.8%. The follow-up duration ranged from 63 days to 20 years (mean, 7.7years), and the total cumulative follow-up was 6014.4 patient-years. Since 1990, residual tricuspid regurgitation (TR) was assessed by transthoracic echocardiography for all patients before discharged from the hospital and during the follow-up period.
2.5 Statistical analysis
All valve-related deaths and complications were defined in compliance with the guidelines established by the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity [8]. Descriptive statistics are reported as mean ± standard deviation for continuous variables and as frequencies and percentages for categorical variables. Late valve-related events were defined as structural valvular deterioration, thromboembolism, valve thrombosis, anticoagulation-related hemorrhage, prosthetic valve endocarditis, paravalvular leakage in the absence of infection, and pannus formation. Valve-related complications were expressed in linearized form. Risk factors for early mortality analysis were performed by 
2-test, Fisher's exact test and the multivariate logistic regression model. Cardiac- or valve-related late deaths were evaluated by univariate analysis of the log-rank test and the stepwise Cox proportional hazards multivariate model. The variables with P
< 0.1 on univariate analysis were entered into a multivariate analysis. Survival curves were described by the Kaplan–Meier method. Statistical analyses were performed on a personal computer using SPSS 11.0 software for Windows (SPSS Inc., Chicago, IL). P
< 0.05 was considered significant.
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3. Results
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3.1 Hospital mortality
Seventy-one patients died within 30 days after surgery, giving a hospital mortality of 8%. The most common cause of early death was low cardiac output syndrome (n
= 49, 69%). Seven patients died from refractory or uncontrollable arrhythmias, five from multi-organ failure, three from sepsis, and two from left ventricular rupture. Other causes of death included cardiac tamponade, air embolism, respiratory insufficiency, acute renal failure, and gastrointestinal bleeding in one patient each.
Univariate analysis revealed NYHA class IV, severe pulmonary hypertension, renal insufficiency, liver dysfunction, ascites, peripheral edema, lower LVEF (<0.4), tricuspid valve replacement as variables with P
< 0.1. With the multivariate logistic regression analysis, the presence of ascites, NYHA class IV and lower LVEF were identified as predictors for hospital death after TVS (Table 3
).
3.2 Long-term survival
During the follow-up period, an additional 264 patients died (late mortality of 30%), of whom 192 (73% of late mortality, 22% of the patient population) were cardiac- or valve-related. The most common cause of late mortality was postoperative congestive heart failure (CHF) (n
= 92, 35% of late mortality). Other cardiac- or valve-related causes included arrhythmias, hemorrhage, endocarditis, thromboembolism, reoperation, myocardial infarction, and unexplained sudden death. The other 72 deaths were due to noncardiac causes. The causes and number of late mortality were listed in Table 4
. The overall 5- and 10-year survival rate (inclusive of hospital mortality) was 71% ± 3% and 59% ± 5%, respectively. The cardiac survival rate including the cases of hospital death was 75% ± 3% at 5 years and 63% ± 4% at 10 years. The event-free survival rate at 5 years and 10 years was 61% ± 6% and 41% ± 13%, respectively (Fig. 1
). The linearized rate of totally late mortality and cardiac- or valve-related mortality was 4.4% per patient-years and 3.2% per patient-years, respectively.
Univariate analysis revealed advanced age (>55 years), preoperative NYHA class IV, peripheral edema and lower LVEF (<0.4) as variables with P
< 0.1. In stepwise Cox proportional hazards multivariate analysis, advanced age, NYHA class IV and lower LVEF were found to be significant predictors of cardiac-related late mortality following TVS (Table 3). The 10-year cardiac survival rate was 45% ± 11% for preoperative NYHA class IV patients and 76% ± 6% for preoperative NYHA class II and III patients (P
= 0.008, log-rank test). The 10-year cardiac survival rate was 41% ± 13% for preoperative lower LVEF patients and 80% ± 5% for preoperative normal LVEF patients (P
= 0.001, log-rank test).
3.3 Late major complications
Thromboembolism occurred in 59 patients (10 deaths) for a linearized rate of 0.98% per patient-years. The freedom from thromboembolism at 10 years was 90% ± 4% (Fig. 2
). Five patients had valve thrombosis, the linearized rate being 0.08% per patient-years, and all of them needed reoperation, one of whom died in the operating room. Ninety-seven patients suffered from anticoagulation-related hemorrhage, leaving a linearized rate of 1.6% per patient-years, 16 of whom with internal bleeding died. Ten-year freedom from anticoagulation-related hemorrhage was 81% ± 5% (Fig. 3
). Thirty-four cases were complicated by prosthetic valve endocarditis, the linearized rate being 0.6% per patient-years. Eleven of them required reoperation, three of whom died, and the other 23 patients were treated conservatively, 13 of whom died. Nine patients had paravalvular leakage with a linearized rate of 0.15% per patient-years, all of whom received reoperation and were alive. Structural valvular deterioration of bioprosthesis occurred in nine patients, giving a linearized rate of 4.3% per patient-years, and all of them received reoperation, two of whom died. No structural valve failure of the mechanical prosthesis was observed.
3.4 Late cardiac reoperation
Thirty-nine late cardiac reoperations were performed during the follow-up period and the causes of the reoperation are displayed in Table 5
. The linearized rate of late cardiac reoperation was 0.65% per patient-years. The 10-year freedom from cardiac reoperation was 91% ± 3%. The interval from initial TVS to reoperation was from 1.8 to 16 years with a mean of 6.9 years. Seven of these 39 patients did not survive the reoperation.
3.5 Late NYHA functional class
On the latest follow-up, 508 patients were still alive. Among them, 137 (27%) were in NYHA class I, 239 (47%) in class II, and 112 (22%) in class III. The other 20 (4%) deteriorated to class IV. In the latest echocardiographic follow-up, all these 508 patients had normally functioning prosthetic valves. Mild (grade 2+) residual TR was observed in 102 cases, moderate (grade 3+) in 39, and no severe (grade 4+) residual TR was found.
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4. Discussion
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Valve surgery for RHD still constitutes a significant number of cardiac valvular operations in Mainland China. Despite substantial improvements in myocardial protection and CPB techniques, TVS for advanced RHD are still challenging for the more advanced state of the disease and complexity of the operation. In addition, outcomes of TVS are often complicated by different underlying pathophysiologic conditions, associated cardiovascular diseases, and concomitant operative procedures. To minimize the impact of all of these factors on early and late outcomes, only patients who received primary selective TVS for isolated advanced RHD were included in the present study. So this cohort accounted for the most homogeneous group of the total of 1137 patients who underwent TVS at our institution from January 1985 to January 2005.
The hospital mortality of 8% in this series compares favorably with that in the majority of other series, which indicated that operative mortality ranged from 13% to 31% [2,9,10]. In our series, all patients were suffering from isolated RHD. These patients were at a younger age. In industrialized countries the patient population may differ, where the population may consist of patients with advanced age and ischemic background. Advanced age is associated with decreased physiologic reserve and increased comorbid factors. We, therefore, believe that operation at younger age may be advantageous for better surgical outcomes. This may be the main reason for our lower hospital mortality in this complex category of patients. Alsoufi and colleagues [9] failed to find the independent risk factors for perioperative mortality after TVS. Gersh and colleagues [4] found preoperative NYHA class IV was the only significant variable influencing hospital mortality. In our series, however, the presence of ascites was found to be the most important risk factor with an odds ratio of 10.7, and NYHA class IV and lower LVEF (<0.4) were also identified as independent predictors for hospital mortality, and this is consistent with Akay and colleagues’ [11] results with the exception of ascites.
A number of reports published many years ago indicated TVS was associated with poor long-term survival, with reported survival rate at 5 and 10 years of 55% and 35%, respectively [5,10]. Some reports published recently, however, showed a better long-term survival has been achieved. Alsoufi and colleagues [9] reported the 5-year and 10-year survival after TVS was 75% and 61%, respectively. Akay and colleagues [11] showed survival rates at 5 and 10 years were 78% and 62%, respectively. In our study, the overall survival rates at 5 and 10 years were 71% and 59%, respectively, comparing a little unfavorably with that of Alsoufi and Akay and colleagues’ series [9,11] and a lot favorably with that of other series [5,10]. We believe, as many other authors also stressed, that improved perioperative and postoperative care contribute much to better long-term survival rates, including improved myocardial protection and CPB techniques, increased experience with complex surgical procedures, substantial improvements in treatment of postoperative CHF, and decreased valve-related complications due to intensive follow-up and extensive education on anticoagulation. In addition, the younger age in our patient population may be another important factor in favor of better long-term survival rates. Carrier and colleagues [12] showed age is the only risk factor significantly correlated with long-term mortality following TVS. Akay and colleagues [11] found NYHA class IV, lower LVEF and increased left ventricular end-diastolic dimension were the risk factors affecting the long-term survival, and they were echoed by Michel and Kara's groups [3,5]. Stephenson and colleagues [13] stressed pulmonary hypertension and emergency operation were also factors influencing late survival. Some authors [14,15] pointed out tricuspid replacement comparing with repair was associated with late mortality. In our series, we identified advanced age, NYHA class IV, and lower LVEF as independent predictors of long-term mortality. There was no emergency operation, and we did not find preoperative pulmonary hypertension, increased left ventricular end-diastolic dimension and tricuspid replacement as independent risk factors.
Valve-related complications have been reported to be more common in patients underwent TVS compared with single or double valve surgery [2,4,10]. In our series, the incidence of valve-related complications, with the exception of incidence of cardiac reoperation, which is higher than that of after single or double vale surgery, is comparable to the reported rate following single or double valve surgery in other recently published series [16,17]. These findings correspond to those reported by other authors [9,12]. We adhered to a low-intensity anticoagulant regimen in which the target PT was maintained at 1.5 times control value. This regimen is optimized to offer sufficient protection against thromboembolism on the one hand and hemorrhage on the other. The concept of INR was implemented in the last decade and exclusively used in the last 5 years. We prefer mechanical prostheses because of younger age of our patient population in which no one was older than 65 years. In our total of 871 patients, only 26 patients received bioprostheses because of contraindications for anticoagulation or special requests. Furthermore, the low incidence of thromboembolism is presumably related to factors such as inherent difference in coagulable states and competence of the individual managing the patient's anticoagulation. The linearized occurrence of thromboembolism and anticoagulation-related hemorrhage were 0.98% per patient-years and 1.6% per patient-years, respectively. There were 27 women patients carried their pregnancy to full term and bore normal children. The oral anticoagulant therapy was substituted with subcutaneous heparin 5,000 units twice daily during the first and last trimester. Warfarin embryopathy and intracerebral hemorrhage in the newborn were not encountered.
There were only nine cases complicated by paravalvular leakage in the present review. The linearized rate of paravalvular leakage was 0.15% per patient-years, which was much lower than that reported by others researchers [18,19]. We believe strongly that interrupted horizontal mattress sutures with felt pledgets are a sine qua non in its prevention, which, as many other authors also emphasized [16,20], provides better valve stability and may eliminate this adverse complication.
In summery, primary TVS for advanced RHD appears to offer satisfactory short- and long-term results with excellent symptomatic improvement. Cardiac-related late mortality following TVS may be improved by early surgical treatment before NYHA class IV or deterioration of LVEF occurs. Long-term valve-related complications rates are similar to patients underwent single or double valve surgery. All of these findings seem to justify aggressive surgical treatment in those with advanced RHD.
The fact is that ‘95% of the 15.6–19.6 million cases of RHD in the world, and the 233 000–492 000 deaths each year due to acute rheumatic fever and RHD, occur in developing countries’ [21], and if the younger age of our patient population was taken into consideration, the current results seem not to be fully satisfactory.
However, a number of limitations are inherent to this analysis design: a retrospective single institution study. Another limitation of the present study is the long time period of the analysis; changes in surgical technique and postoperative care along time may influence outcome and prognostic factors.
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Abstract
1. Introduction
