Nature's machines : autologous skeletal muscle for circulatory support

Skeletal muscle fatigue and insufficient power output were two biological constraints impeding the application of this endogenous energy source for support of the failing ventricle. Our ability to manipulate muscle phenotypic expression by a transforming and continuous low frequency electrical stimulation and the development of synchronizable pulse-train stimulators have overcome these historical obstacles.This thesis addresses the hypothesis that fatigue-resistant transformed skeletal muscle can support the failing circulation. The work is divided into two major sections involving animal laboratory and clinical human experimentation.In acute dog models of heart failure we have demonstrated the feasibility of transformed latissimus dorsi muscle assisting the heart in various configurations: (1) to power a potentially implantable pericardiovascular mechanical assist device and (2) in hybrid union for biventricular failure with cardiomyoplasty and mechanical support for the right and left ventricles respectively.In another series of experiments using coronary sinus drainage as a surrogate marker for epicardial coronary flow we did not witness any compromise of epicardial coronary flow by the overlying muscle graft.In our clinical series of 5 patients with chronic heart failure, who were all rejected for transplantation and underwent dynamic cardiomyoplasty, our follow-up investigations have revealed insights into appropriate patient selection criteria and the potential underlying pathophysiologic mechanisms of this new surgical technique in the palliation of refractory heart failure

Use of an apical suctioning device for placement of a posterior epicardial defibrillator patch: A case report

We report a case of a 43-year-old man with dilated cardiomyopathy and intractable ventricular tachycardias who did not respond to percutaneous implantable cardioverter defibrillator therapy and required implantation of epicardial patches. An apical suctioning device was used to retract the apex of the heart outside the mediastinal domain. The device provided excellent exposure and hemodynamic stability to safely implant the posterior epicardial patch

Aortic valve-sparing repair with autologous pericardial leaflet extension has low long-term mortality and reoperation rates in children and adults

We sought to establish whether there was a difference in outcome after aortic valve repair with autologous pericardial leaflet extension in pediatric and adult populations. In our study, 128 patients (pediatric and adult) underwent valvular pericardial extension repair at our institution from 1997 through 2006. The patients were divided into either the pediatric group (< or =18 years of age; n = 54/128, 42%), with a mean age of 8.4 +/- 5.4 (range, 0-17 years), or the adult group (n = 74/128, 58%), with a mean age of 48.9 +/- 19.7 (range, 19-85 years). The endpoints of the study were mortality and reoperation rates. Thirty-day mortality for the adult group was 0, and for the pediatric group it was 1/54 (1.8%), with no statistical difference (P = .1) between the groups. Late mortality for the pediatric group was 2/54 (3.7%) and in the adult group was 2/74 (2.7%). There was no statistical difference (P = .12) between the groups. In the pediatric group, there were 6 total reoperations (6/54) in 5 patients, with one patient undergoing reoperation twice. From these 6 cases, 3 were re-repair and 3 had aortic valve replacement; the mean interval between original repair and reoperation was 4.3 +/- 2.5 years (range, 0.1-7.7 years). In the adult group, there were 5 total reoperations (5/74). From these 5 cases, 3 had aortic valve replacement and 2 re-repair; the mean interval between original repair and reoperation was 3.5 +/- 3 years (range, 0.1-7 years). There was no statistical difference in the reoperation rate between the 2 groups (P= .38). At late follow-up, 82% of all patients in the adult group had no aortic regurgitation or only a trace (grades 0 and 1) and 78% of all patients in the pediatric group had no aortic regurgitation or only a trace (grades 0 and 1). There was no statistical difference in either aortic regurgitation (P = .06) or aortic stenosis (P = .28) between the 2 groups. Aortic valve repair with autologous pericardial leaflet extension has low mortality and morbidity rates, as well as good mid-term durability in both the pediatric and the adult groups

Aortic valve-sparing repair with autologous pericardial leaflet extension has a greater early re-operation rate in congenital versus acquired valve disease

Objective: We sought to establish whether there was a difference in outcome after aortic valve repair with autologous pericardial leaflet extension in acquired versus congenital valvular disease. Methods: One hundred and twenty-eight patients underwent reparative aortic valve surgery at our institution from 1997 through 2005 for acquired or congenital aortic valve disease. The acquired group (43/128) (34%) had a mean age of 56.4 ± 20.3 years (range, 7.8–84.6 years) and the congenital group (85/128) (66%) had a mean age of 16.9 ± 19.2 years (range, 0.3–82 years). The endpoints of the study were mortality and reoperation rates. Results: Thirty-day mortality was 0/43 (0%) in the congenital group and 1/85 (1.1%) in the acquired group. Late mortality in the acquired group was 3/43 (7%) and 3/84 (3.5%) in the congenital group (neither early nor late proportion of mortality is significantly different between the two groups, according to the nonparametric Binomial test for proportions). There were 13 total reoperations among 11 patients: 1/43 (2.3%) in the acquired group and 10/85 (11.7%) in the congenital group (p = 0.07). Two patients from the congenital group were reoperated on twice. The mean interval between original repair and reoperation was 3.6 ± 5 years (range, 0–7 years) for acquired and 3.5 ± 2.5 years (range, 0–7 years) for the congenital group (Wilcoxon 2-sample test, p = 0.7). Total early reoperation rate (≪30 days after first surgery) was 11/128 (8.5%); for the congenital group 9/85 (10.5%) and for the acquired group 2/43 (4.6%). Early reoperation rate was significantly higher among the congenital group (p = 0.013). The remaining patients are well at mean follow-up of 2.8 ± 2.4 years (range 0–7.9). In the acquired group, the mean postoperative aortic regurgitation and stenosis grade by echocardiography was 0.5 ± 0.3 (scale, 0–4) and 0.3 ± 0.1, respectively. In the congenital group, the follow-up, mean aortic regurgitation and stenosis were 0.9 ± 0.8 and 0.5 ± 0.3, respectively. Conclusions: There was no significant difference in early or late mortality and late reoperation rate between the two groups. Early reoperation rate was higher in the congenital versus the acquired aortic valvular disease group. This study supports the fact that the valve-sparing technique is safe and reproducible and repeatable in patients with acquired valve disease