Dr. Kaiser, Dr. Pairolero, members and guests:
Partial left ventriculectomy, the Batista operation, has been performed as an alternative treatment of severe cardiomyopathies. The primary objective of this procedure is to decrease left ventricular wall tension by the reduction of chamber volume/mass relationship resulting in the partial restoration of myocardial contractility and to slow progression of the underlying disease.
At the Heart Institute of Sao Paulo University in Brazil, a prospective study about the clinical and the left ventricular function effects of partial left ventriculectomy has been conducted since 1995 and the purpose of this presentation is to discuss with you the midterm results of this procedure performed when necessary in association with mitral valve repair or replacement in 37 patients with advanced heart failure caused by idiopathic dilated cardiomyopathy. Sixteen patients were New York Heart Association Class III and 21 were in persistent Class IV at the moment of partial ventriculectomy indication despite attempts to optimize medical therapy. Nine of these patients also had reversible cardiogenic shock with the use of intravenous inotropic drugs. Partial left ventriculectomy was performed according to the technique initially described by Randas Batista. A slice as large as possible of left ventricular myocardia was resected between the papillary muscle from the apex of the heart up to 2 or 3 centimeters from the mitral annulus. The left ventricle was then repaired with a double suture anchored in bovine perecardium strips. The resected myocardial specimen measured around 11 centimeters in length and approximately 5 centimeters in width, which corresponds to an estimated percentage of 19 to 20 percent of left ventricular wall.
Partial left ventriculectomy was performed as an isolated procedure in 8 patients and 22 patients had this procedure associated with mitral annuloplasty. Two other patients had this procedure associated with mitral valve replacement and in 5 patients, mitral and tricuspid valve annuloplasty were performed. Seven patients died at the hospital period and the 30 patients discharged from the hospital were followed for a mean of 15 months, from 2 to 23 months. Thirty patients were submitted to radioisotopic angiography and to right heart catheterization during the first post-operative month and these studies were subsequently performed in 22 patients at 6 months, in 16 patients at 12 months, and in 10 patients at 2 years of follow-up. Radioisotopic angiography demonstrated the significant improvement of the left ventricular ejection fraction from values around 17% to 26% at the first month of follow-up. This improvement was maintained for up to two years of follow-up in the patients with completed study. The modification of left ventricular ejection fraction occurred associated with the decrease of left ventricular diastolic volume on the order of 27% at the first post-operative month. Similar values of this parameter were observed during the first year of follow-up; however, left ventricular diastolic volume tended to increase after the first year after two years of follow-up. Hemodynamic evaluation showed a significant improvement of cardiac index and of stroke index immediately after the operation and this improvement was also maintained from six months to 2 years of follow-up. Pulmonary wedge pressure values decreased significantly from the pre-operative period at the first month of follow-up from values around 26 to values around 17 mmHg. However, this parameter also tended to increase after one year of follow-up.
Regarding the clinical condition, significant improvement of New York Heart Association functional class was observed in the surviving patients at 6 months of follow-up. This improvement was also maintained in later follow-up and 9 patients are currently in functional Class I, 8 in functional Class II and only 3 in functional Class III. On the other hand, another 9 patients died and another patient was submitted to heart transplantation after 7 months of follow-up. The causes of death at the immediate post-operative period were ventricular dysfunction in 5 patients, recurrent ventricular tacyhcardia in 1 patient, disseminated intravascular coagulation in 1 patient and, in the later follow-up, 5 patients died due to heart failure progression and 4 patients died due to to arrhythmia-related events. The actuarial survival rates were 62 percent at 3 months, and 56 percent at 6 months of follow-up, while it is interesting to note that no mortality and also no necessity of heart transplantation indication occurred after the first 6 months of partial left ventriculectomy follow-up for up to 2 years. Univariate analysis of preoperative and surgical risk factors showed that only the level of myocardial cells hypertrophy in the resected left ventricular myocardium was significantly associated with the unfavorable outcome observed after partial left ventriculectomy in the first month of follow-up. No correlation was observed between early survival after this procedure and pre-operative left ventricular function variables, left ventricular diastolic dimension, plasma norepomephrine levels and also patients pre-operative clinical status, the percentage of myocardial fibrosis in the resected myocardium and also the percentage of left ventricular resection. With regard to the influence of myocardial cells diameter on partial left ventriculectomy outcomes, this curve, obtained by logistical regression, shows that the risk of death or necessity of urgent heart transplantation, increases exponentially and achieved values of more than 25 percent when the mean myocytes diameter in this patient population was greater than 22 microns. The survival curves, according to this variable, show that the 2 year survival of patients with a less important myocardial cells hypertrophy was around 74 percent, while those patients with severe myocytes compromise presented a survival rate of only 31 percent at the same period.
Interpretation of the current clinical experience with partial left ventriculectomy is limited. Nevertheless, we can conclude that this surgical procedure associated when necessary with mitral insufficiency correction improves left ventricular function and ameliorates cogestive heart failure for up to 2 years of follow-up. On the other hand, although early survival after this operation appears to be by a high incidence of heart failure progression and arrhythmia-related events, the identification that these events seem to be influenced by myocardial cells compromised opens the possibility of a pre-operative identification of patients with predominant anatomical remodeling instead of patients with severe myocardial damage. This fact has the potential to improve partial left ventriculectomy outcomes and contribute to place this procedure as a real alternative in the spectrum of surgical treatment of heart failure. I thank the Society for the opportunity to present this paper.