Lawrence H. Cohn

Tricuspid Regurgitation Secondary to Mitral Valve Disease: When and How to Repair

The etiology of tricuspid regurgitation (TR) in North American patients with mitral valve disease is almost entirely nonrheumatic functional dilatation of the tricuspid annulus. In mild TR, no operative therapy is necessary since relief of the left sided valve lesion will suffice to bring the pulmonary pressure down and, consequently, relief of TR for moderate (2+ to 3+) TR. We have used a technique of posterior annuloplasty using a DeVega type double running braided suture beginning at the commissure of the anterior and posterior leaflets and running to the commissure between the septal and posterior leaflets, and tied over an obturator. The technique takes less than 10 minutes. Seventy‐one patients in the past 10 years have been treated with this technique with virtually 100% relief of TR. For severe TR, we advocate the use of Carpentier‐Edwards annuloplasty ring with interrupted sutures (16 patients). We believe severe TR requires a fixed annulus for virtually the entire circumference of the valve. Functionally regurgitant tricuspid valves should be reconstructed and not replaced. The use of repair techniques for moderate (posterior annuloplasty) or severe (Carpenter‐Edwards tricuspid annuloplasty ring) TR will be satisfactory for virtually all patients with this lesion. (J Card Surg 1994;9[Suppl]:237–241)

Improved Surgical Approach to Left Atrial Appendage Aneurysm

Left atrial appendage aneurysm is a rare anomaly, which usually presents with arrhythmia or cerebral embolism. Diagnostic evaluation traditionally required cardiac catheterization, and surgical resection required cardiopulmonary bypass. Utilizing intraoperative transesophageal echocardiography and surgical stapling devices, we have streamlined our operative technique, allowing resection of a left atrial appendage aneurysm without cardiopulmonary bypass. This report of two cases treated over the past decade demonstrates the evolution of our surgical technique.

Determinants of Outcomes for Postcardiotomy VAD Placement: An 11-Year, Two-Institution Study

abstract  Objective: Ventricular assist device (VAD) placement after postcardiotomy failure is associated with a high mortality. We sought to determine prognostic factors in order to help better select patients who may benefit from VAD placement. Methods: From January 1992 to January 2003, 63 patients out of approximately 30,000 cardiac surgery patients (0.21%) developed postcardiotomy failure requiring VADs. Planned VAD for bridge to transplant or bridge to recovery were excluded. Multivariate logistic regression analysis, based on pre‐VAD placement parameters, was used to determine prognostic factors for in‐hospital 30‐day mortality. Results: Overall operative mortality was 73% (46 of 63). Multivariate logistic regression analysis identified median age ≤50 (each additional year) (OR = 0.85, 95% CI = 0.77 to 0.95, p = 0.004) and median base deficit ≥0 mEq/L (each additional mEq/L) prior to VAD placement (OR = 0.60, 95% CI = 0.48 to 0.91, p = 0.012) to be independent predictors of improved 30‐day survival. Conclusions: Postcardiotomy failure is a rare event but is associated with a very poor prognosis despite salvage therapies utilizing VADs. Age ≤50 years and base deficit ≥0 (mEq/L) prior to VAD placement are associated with improved 30‐day survival.

The long-term follow-up of the Hancock Modified Orifice porcine bioprosthetic valve.

The Hancock Modified Orifice valve is a specially fabricated, trileaflet porcine valve, which has been in clinical use at the Brigham and Womens Hospital since 1976. Three hundred seventy‐nine aortic valve replacements with this device were implanted from 1976 to 1985; 305 were isolated aortic valve replacements and 74 were in association with a mitral valve bioprosthesis. The 305 patients undergoing isolated aortic valve replacement, a Food and Drug Administration patient group, are the subject of this article. The mean valve size was 22.5 mm, with 115 21‐mm valves used. The mean functional preoperative class was 3.2; 99 of 305 patients (32.5%) underwent concomitant coronary artery bypass grafting. There were six operative deaths (2%). Patients were followed from 6–14 years (mean 7.4 years), and analysis was completed in early 1991. The 10‐year actuarial calculation of survival freedom from reoperation, thromboembolism, structural valve degeneration, perivalvular leak, infectious valve degeneration, and total morbidity and mortality are presented.

Dynamic Aortomyoplasty: Clinical Experience and Thoracoscopic Surgery Feasibility Study

Abstract Background: Surgical procedures using the latissimus dorsi (LD) muscle to assist chronic heart failure inflict major trauma on severely sick patients. A less invasive approach may prove beneficial. The aim of this article is to review our clinical and experimental approaches of dynamic aortomyoplasty (AMP) and emphasize the necessity to reorient surgical technique towards new directions and a less invasive thoracoscopic approach. Materials and Methods: A clinical pilot study on dynamic descending AMP started in June 1995 and included four patients. Two of them could benefit from LD counterpulsation, surviving 6 months and 18 months. Following this clinical experience, we investigated, on an animal model, minimally invasive thoracoscopic surgery for this procedure. Twelve goats underwent endoscopic LD harvest and video‐assisted aortic wrap, and were studied after surgical recovery from an anatomical and functional standpoint. Results: Clinical AMP using open techniques provided extraaortic counterpulsation in NYHA Class IV patients contraindicated for other surgical therapies. However, surgical technique and strategy needed improvements for optimal cardiac assistance and better patient outcome. Minimally invasive thoracoscopic surgery was feasible and reproducible in goats, achieving improved anatomy and physiology as compared to the open technique in humans. When appropriate the wrapping technique and stimulation protocol were used, an optimal counterpulsation was demonstrated. We concluded that thoracoscopic AMP may provide a minimally invasive approach to cardiac assistance and thus, a new surgical option for patients presenting with chronic heart failure. (J Card Surg 1998;13:60–69)

Valve Replacement for Infective Endocarditis: An Overview

Abstract Infective endocarditis, both in the native and prosthetic valve, presents a tremendous challenge to the cardiologist and cardiovascular surgeon, as well as the infection specialist. The timing of surgery is critical but it would appear that aggressive surgical intervention is indicated when there is persistent sepsis, continuing congestive heart failure, signs of nonfatal emboli, or in association with certain organisms such as staphylococcus, pseudomonas, or fungal organisms. Cardiac catheterization would not appear to and greatly to the diagnosis except to document the presence of coronary artery disease. The risk of surgery in patients with no annular abscess Is low but the recurrence rate tends to be highly dependent on the organism. Similarly, patients who have annular abscesses tend to provide the greatest challenge for the surgeon and despite the use of newer prosthetic and biological prostheses and an overall more aggressive approach, this pathological entity, particularly in conjunction with prosthetic valve endocarditis, has a high mortality and a high recurrence rate.

Real-time visualization and quantification of retrograde cardioplegia delivery using near infrared fluorescent imaging.

Abstract  Background and Aim: Homogeneous delivery of cardioplegia is essential for myocardial protection during cardiac surgery. Presently, there exist no established methods to quantitatively assess cardioplegia distribution intraoperatively and determine when retrograde cardioplegia is required. In this study, we evaluate the feasibility of near infrared (NIR) imaging for real‐time visualization of cardioplegia distribution in a porcine model. Methods: A portable, intraoperative, real‐time NIR imaging system was utilized. NIR fluorescent cardioplegia solution was developed by incorporating indocyanine green (ICG) into crystalloid cardioplegia solution. Real‐time NIR imaging was performed while the fluorescent cardioplegia solution was infused via the retrograde route in five ex vivo normal porcine hearts and in five ex vivo porcine hearts status post left anterior descending (LAD) coronary artery ligation. Horizontal cross‐sections of the hearts were obtained at proximal, middle, and distal LAD levels. Videodensitometry was performed to quantify distribution of fluorophore content. Results: The progressive distribution of cardioplegia was clearly visualized with NIR imaging. Complete visualization of retrograde distribution occurred within 4 minutes of infusion. Videodensitometry revealed retrograde cardioplegia, primarily distributed to the left ventricle (LV) and anterior septum. In hearts with LAD ligation, antegrade cardioplegia did not distribute to the anterior LV. This deficiency was compensated for with retrograde cardioplegia supplementation. Conclusions: Incorporation of ICG into cardioplegia allows real‐time visualization of cardioplegia delivery via NIR imaging. This technology may prove useful in guiding intraoperative decisions pertaining to when retrograde cardioplegia is mandated.

An External Aortic Root Device for Decreasing Aortic Regurgitation: In Vitro and In Vivo Animal Studies

Objectives: The purpose of this study was to determine if a device placed externally around the aortic root decreases regurgitant flow in acute aortic regurgitation. Background: Aortic regurgitant flow is dependent on central aortic pressure and the aortic root and leaflet geometry. It may be possible to decrease aortic regurgitant severity by reducing aortic root size or dimension changes. Methods: Aortic regurgitation was created in eight calf heart specimens suspended in a continuous flow system. Retrograde and antegrade aortic flow and distending aortic pressure were measured at baseline and after placement of an external aortic device at the level of the aortic annulus. In two additional specimens, the incompetent aortic valve was visualized fiberoptically before and after placement of the external device. Acute aortic regurgitation was created surgically in four live calves by excising a portion of the aortic leaflets. Antegrade and retrograde flow, left ventricular pressure, and central aortic pressure were measured at baseline, after creation of aortic regurgitation, and after placement of the external device. Results: In the in vitro calf specimens, regurgitant flow decreased from 46.9 cc/sec to 15.1 cc/sec (66.0%± 21.8% decrease) after placement of the external device (p < 0.001). The regurgitant orifice area decreased from 0.13 ± 0.04 cm2 to 0.04 ± 0.02 cm2 after device placement (p < 0.001). Antegrade flow was reduced to a smaller extent (20.0%± 19.2% decrease) by the device (p < 0.05). Placement of the device around the aorta resulted in improved coaptation of the leaflets with a marked reduction in defect size by endoscopic visualization. Use of the external aortic device was associated with improvement in aortic regurgitant severity in three of four calves with surgically created aortic regurgitation. Concluslons: In these preliminary studies, acute experimental aortic regurgitant severity is decreased by the use of an external aortic device, probably due to reduction in aortic annular dimension changes and improved aortic leaflet apposition. Further studies are needed to determine the effectiveness of this device in chronic aortic regurgitation. (J Card Surg 1994;9:304–313)