Akira T. Kawaguchi

Myocardial Revascularization of the Beating Heart in High‐Risk Patients

Objective: Myocardial revascularization without cardiopulmonary bypass (CPB) has been proposed as an alternative technique in patients at high risk for conventional coronary artery bypass grafting (CABG). The purpose of this article is to evaluate the potential benefit of such an approach. Methods: We retrospectively evaluated the perioperative results of off‐pump CABG (OPCAB) performed from January 1995 to December 1999. Patients were divided into three groups on the basis of their preoperative risk factors: age greater then 80 years, reoperative CABG, and left ventricular ejection fraction percentage (LVEF%) less than 40%. The three subgroups were compared with patients operated on‐CPB (ONCAB) during the same period of time. A total of 172 octogenarians had ONCAB versus 97 OPCAB, 307 reoperations were ONCAB versus 274 OPCAB, and 514 patients with LVEF% less than 40% were operated ONCAB versus 220 OPCAB. Results: Preoperative comorbidities were homogeneously distributed in the OPCAB and ONCAB groups. More extensive coronary artery disease was found in the ONCAB groups. A trend for a lower number of perioperative complications was reported in the OPCAB groups. Freedom from overall complications was significantly higher (p < 0.005) in the OPCAB group. Actual mortality rates in the OPCAB and ONCAB groups were comparable (p = NS). Conclusions: CABG can be performed safely without CPB in patients with a high preoperative risk profile. Freedom from perioperative complications is markedly higher when the OPCAB approach is utilized.

Partial Left Ventriculectomy in Patients with Dilated Failing Ventricle

Abstract Background: While partial left ventriculectomy (PLV) improves left ventricular energetic efficiency, concomitant reduction in mitral regurgitation may improve ventricular function. Methods: Two hundred ninety‐five patients undergoing lateral ventricular wall excision between the papillary muscles (lateral PLV) and 101 patients with an additional excision of papillary muscles and mitral valve replacement (extended PLV) were compared with 65 patients undergoing excision of anterior wall or ventricular aneurysm (anterior PLV). Results: All patients had reduced functional capacity, New York Heart Association (NYHA) Class 111 to IV (3.62 ± 0.49). Etiologies were cardiomyopathy (37.3%), coronary artery disease (32.3%), valvular disease (19.7%), Chagas disease (7.8%), and others (2.8%). Patients undergoing lateral and extended PLV had cardiomyopathy as the primary cause of heart failure, while a majority of anterior PLV patients had ischemic disease. Associated procedures included mitral valvuloplasty or replacement (lateral PLV 67%, extended PLV 100%, anterior PLV 40%) and tricuspid annuloplasty (67%, 76%, 28%, respectively.) In each group after surgery, end‐systolic dimension decreased more than end‐diastolic dimension despite reduced mitral regurgitation. Although extended PLV resulted in greater volume reduction and less mitral regurgitation, these patients had delayed recovery and poor survival. Patients with valvular disease had the most advanced myocardial hypertrophy with the best survival, while those with Chagas disease had more severe myocarditis, interstitial fibrosis, and the poorest survival. Conclusion: Lateral PLV improved hemodynamics and functional capacity as much as aneurysmectomy by reducing ventricular volume and mitral regurgitation. Inclusion and exclusion criteria have to be sought to make PLV safer and more effective.

Factors affecting ventricular function and survival after partial left ventriculectomy.

Abstract Background: Partial left ventriculectomy (PLV) helps some patients but is deleterious in others. Selection of patients who will benefit from PLV, and exclusion of those who will not is necessary for safe and effective application of the procedure.

Transeventricular Mitral Annuloplasty in a Patient Undergoing Partial Left Ventriculectormy

A 70‐year‐old male patient with heart failure resulting from dilated cardiomyopathy underwent a partial left ventriculectomy between the papillary muscles and a newly devised transventricular mitral annuloplasty. Intraoperative transesophageal Doppler echocardiography revealed reduced ventricular dimensions and corrected mitral insufficiency with unchanged ventricular filling patterns, allowing prompt recovery despite unchanged myocardial pathology.

Improved Left Ventricular Contraction and Energetics in a Patient with Chagas' Disease Undergoing Partial Left Ventriculectomy

A 43‐year‐old patient with heart failure, precluded from heart transplantation or dynamic cardiomyoplasty because of Chagas disease cardiomyopathy, mitral regurgitation, and ventricular mural thrombi, underwent mitral valvuloplasty and partial left ventriculectomy (PLV) between the papillary muscles. Intraoperative pressure‐volume relationship analyses suggested improvement in left ventricular contraction, energetics, isovolumic relaxation, and mitral valve competency. These improvements allowed prompt, short‐term recovery despite unchanged myocardial pathology, which suggests that a surgical approach can after anatomic‐geometric factors and achieve clinical improvement in a dilated failing ventricle.

Partial Left Ventriculectomy for Patients with Ischemic Cardiomyopathy

Background: Partial left ventriculectomy (PLV) has been performed in patients with dilated cardiomyopathy (DCM), but improved myocardial energetics may make PLV useful also for ischemic cardiomyopathy (ICM) unamenablis to conventional treatment. Methods: Of 262 patients undergoing PLV, 94 patients with ICM as the underlying pathology were analyzed and compared with 168 patients with DCM. Results: ICM patients were older (57.3 years vs 50.9 years, p = 0.0001) and heavier (69.7 kg vs 65.9 kg, p = 0.039) than those with DCM, but ventricular end‐diastolic and end‐systolic dimensions were similar with comparably depressed fractional shortening (16% vs 15%, p = 0.294) and equally severe functional limitation [New York Heart Association (NYHA) Class 3.7 vs 3.6, p = 0.734]. A majority of patients in both groups underwent lateral PLV (76% vs 74%, p = 0.883) with myocardium excised between papillary muscles and simultaneous mitral valvuloplasty (41% vs 74%, p < 0.0001). Because ICM patients required coronary artery bypass grafting (CABG) more frequently (79% vs 0.6%, p < 0.0001), operation was more extensive in terms of bypass time (74 minutes vs 47 minutes, p < 0.0001), percentage requiring cardiac arrest (43% vs 19%, p < 0.0001), and arrest duration (34 minutes vs 28 minutes, p = 0.280), but all had similar resection and postoperative ventricular dimensions. Nonetheless, ICM patients required shorter intensive care unit (ICU) time (4.4 days vs 5.9 days, p = 0.048) and similar postoperative hospital stays, resulting in similar hospital survival rates (69% vs 71%, p = 0.778) and functional capacity in long‐term follow‐up. Conclusions: Results suggest that PLV can be performed in patients with ICM with comparable risks and benefits as in DCM. Relative efficacy of CABG and mitral repair as compared to volume reduction remains to be studied.

Perioperative Ventricular Arrhythmias in Patients Undergoing Partial Left Ventriculectomy

Background: Although incidence of ventricular arrhythmias after partial left ventriculectomy (PLV) has been reported, there are no studies comparing incidence before and after PLV. Although operative scars may give rise to arrhythmias, improved energetic efficiency after PLV may decrease their incidence. Methods: Pre‐ and postoperative ventricular arrhythmias were monitored by Holter ECG and analyzed in 17 patients undergoing PLV in Curitiba, Brazil. Results: Although total 24‐hour heart beat (THB) increased significantly (p = 0.018), ventricular premature contractions (VPCs) decreased markedly (p = 0.036), excluding one patient dying in low cardiac output (LOS) who had terminal arrhythmias increased multifold. In the remaining 16 patients, VPC pairs were also reduced significantly on the average (p = 0.038). In contrast, ventricular tachycardia (VT; more than three consecutive VPCs) disappeared in five patients, decreased in two patients, and newly occurred in four patients, with five patients showing no change; one of them developed a prolonged VT, successfully reversed by external cardioversion. Conclusions: Despite notable significant increase in THB immediately after PLV, PVC and PVC pairs were significantly decreased in contrast to VT, which disappeared in some patients and newly occurred in other patients, remaining constant on the average. Sustained VT occurring in a patient with all other arrhythmias suppressed may suggest a unique electrophysiological substrate, may justify prophylactic use of amiodarone or an implantable cardioverter‐defibrillator, and may underscore the importance of further and extended studies.

Mitral regurgitation after partial left ventriculectomy as the cause of ventricular redilatation.

Background: It remains unclear whether ventricular redilatation after partial left ventriculectomy (PLV) is due to underlying pathology or to continued volume overload amenable to surgery. Methods: Among patients undergoing PLV, 32 had Doppler echocardiography preoperatively, immediately after surgery (> 1 week), early after surgery (1–3 months), and late after surgery (8–14 months). Patients were divided into groups with mitral regurgitation (MR; MR+, n = 16) and without postoperative MR (MR‐, n = 16) and were compared for ventricular size, performance, and survival. Results: After initial surgical reduction, left ventricular dimension on average gradually increased back to the preoperative level in subgroups of patients with valvular disease and cardiomyopathy and in all patients combined. Most patients showed drastically reduced left ventricular dimension early after PLV. In MR+ patients, dimension increased back to the preoperative level within 3 months after surgery, whereas the MR‐ group maintained reduced dimension throughout the first year in all patients combined and in a subgroup of patients with cardiomyopathy. Occurrence of significant MR after PLV appeared to be related to severity of fibrosis in excised myocardium but not to severity of preexisting MR, etiology, or performance of mitral valvuloplasty. Conclusions: Early postoperative MR, residual or new, appeared to play an important role in dictating early hemodynamics and late outcome in patients undergoing PLV. Results suggest an aggressive simultaneous approach to abolish MR. Causative role of myocardial fibrosis remains unclear and needs further study.

Angiographic and Hemodynamic Follow‐Up of Patients After Partial Left Ventriculectomy

Abstractu2002 Angiographic, Doppler‐echocardiographic and hemodynamic studies early (+6 days) and late (+180 days) after partial left ventriculectomy (PLV) on 24 patients revealed that PLV decreased end‐systolic volume (or dimension) more than the end‐diastolic volume (or dimension), improving stroke volumes (or contractile excursion), and doubling ejection fraction (or fractional shortening). Results of PLV appeared to depend on a balance between improved systolic contractility and reduced diastolic performance. All these survivors had improved diastolic relaxation, suggesting myocardial viability is a prerequisite for PLV to be successful.

Perioperative hemodynamics in patients undergoing partial left ventriculectomy.

Objectives: Effects of partial left ventriculectomy (PLV) were studied by analyzing porioperative hemodynamics with measurements of left ventricular (LV) pressure‐volume (PV) relationships and thermodilution catheter measurements in the pulmonary artery. Methods: Between July and October 1996, 43 consecutive patients underwent PLV with and without mitral valvuloplasty with a thermodilution catheter and PV loop analysis immediately before and after surgery. Patients were 52 ± 13 years and 67 ± 13 kg, with reduced functional capacity (New York Heart Association 3.3 ± 0.3) due to cardiomyopathy (24), ischomic disease (13), valvular disease (3), and Chagas disease (3). Results: PLV required cardiopulmonary bypass for 44 ± 24 minutes, with the heart arrested in 10 patients for 26 ± 22 minutes for coronary artery bypass grafting (8), aortic valve replacement (2), and autotransplantation (2). Two patients failed to come off bypass, six died in the hospital and 35 (35 [81.4%] of 43) were discharged. Changes in PV loops included decreased end‐diastolic and end‐systolic volume, resulting in no change in stroke volume. Pulmonary artery wedge pressure decreased despite elevated end‐diastolic pressure. Ejection fraction, end‐systolic elastance (E‐max), afterload recruitable stroke work, and volume intercepts all improved and resulted in similar stroke work with less energy expenditure (less PV area), thus improving myocardial energetic efficiency. Conclusion: Results suggest that PLV improves systolic function but decreases diastolic compliance, which results in reduced net ventricular function immediately after surgery. Thus, immediate hemodynamic improvements appeared to derive from reduced severity in mitral regurgitation and perioperative load manipulation. Improved myocardial energetics may ameliorate LV function and improve the course of underlying myocardial disease.