We present a case of a 34-year-old male with dilated cardiomyopathy in whom we performed a new surgical procedure; Le., ventricular volume reduction to improve function. This initial human experience was preceded by a series of ten sheep in which we demonstrated that by enlarging the left ventricle (LV), the ejection fraction was reduced, and by restoring normal diameter, the LV function returned to normal. (J Card Surg 7996;77:96-97)Over the last 45 years, we have observed that all animal hearts have the same muscle mass ratio (M = 4.18.R3. M = muscle mass; R = heart radius). Consequently, if any heart increases its diameter for any reason, the muscle mass has to increase to the cubic of each diameter increment in order to maintain normal left ventricular (LV) function. We performed experiments in sheep. By reducing the diameter of dilated LVs, their function improved.
MATERIALS AND METHODSWe operated on a series of ten sheep, and obtained ejection fractions (EFs) preoperatively by cardiac catheterization and epicardial and transesophageal echocardiogram, where we could observe normal LV function (EF = 45%). On cardiopulmonary bypass (CPB), we divided the LV from the apex of the heart between the papillary muscles to the mitral valve annulus. A large pericardial patch was inserted to increase the ventricular diameter. None of the sheep came off bypass, and their EF fell down to 9%. Interestingly, the EF was low because the remaining normal heart muscle contractility was low when the diameter increased. CPB could be discontinued by removing the patch and returning the ventricle to previous normal measurements. The EF then returned to preoperative levels.
CASE REPORTR.M., a 34-year-old male, was admitted August 1994 with heart failure New York Heart Association Class IV. There was peripheral edema and severe orthopnea. Cardiac catheterization ( Fig. 1) showed dilated cardiomyopathy with an EF of 17%.We proceeded with LV volume reduction by resecting a slice of LV between both papillary muscles, from the apex of the heart to the mitral annulus. The LV was repaired with a single 2-0 polypropylene suture. There were no problems weaning from bypass.
RESULTSOne week postoperatively, we repeated the catheterization. The EF went up to 37% (Fig. 2). The patient had an uneventful postoperative course, and 2 months later, we repeated all of the laboratory data and the EF was 44%. Presently the patient is living a normal life.As of October 1995, we have performed the same operation on 154 patients.
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.
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.
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.
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