Alexandros N. Karavas

Minimally invasive mitral valve repair suggests earlier operations for mitral valve disease

OBJECTIVE We began minimally invasive mitral valve surgery in August, 1996, to reduce hospital costs, to improve patient recovery, cosmetic appearance, and to decrease trauma, yet maintain the same quality of surgery. To validate this approach we reviewed our entire experience through May 2002. METHODS From August 1996 to May 2002, we performed 413 minimally invasive mitral valve operations including 51 mitral valve replacements and 362 mitral valve repairs. Excluding 4 robotically assisted repairs, we evaluated 358 patients, using the mitral valve repairs as the basis for this retrospective survey. These operations were performed through a 6- to 8-cm minimally invasive incision, beginning with parasternal and, most recently, lower ministernotomy (181 patients). The mitral valve reparative techniques include repair of 94 prolapsed anterior leaflets, posterior leaflet resection, leaflet advancement, commissuroplasty, Polytetrafluoroethylene (PTFE; Gore-Tex, W. L. Gore & Associates, Inc, Flagstaff, Ariz) chordal placement, and ring annuloplasty. Cannulation sites varied but primarily utilized a miniaturized system of 24F catheters in both the inferior and superior venae cavae with assisted venous suction. The Cosgrove ring was used in 95% of the patients undergoing this procedure. RESULTS The operative mortality was 0/358. Perioperative morbidity included a 26% incidence of new atrial fibrillation, 2% incidence of pacemaker implantation, 0.5% incidence of deep sternal wound infection, and 1.9% incidence of stroke after an operation. There were 10 arterial and 3 venous complications. The mean length of stay was 6 days and 208 patients stayed < or =5 days. Only 25% of the patients underwent homologous blood transfusion. The mean follow-up was 36 months with 1.4% lost to follow-up. There were 12 late deaths and a survival at 5 years of 95%. There were 21 valves requiring reoperation for structural valve failure of 5.8%. The probability of freedom from reoperation at 5 years was 92%. CONCLUSION This study documents the safety of minimally invasive mitral valve repair surgery in 358 patients. It also documents a low incidence of homologous blood use, requirement for post-hospital rehabilitation, and general morbidity.

Management of mild aortic stenosis during coronary artery bypass surgery: an update, 1992-2001.

Abstract  Background:“Prophylactic” aortic valve replacement (AVR) in patients with asymptomatic, mild‐to‐moderate aortic stenosis (AS) at the time of CABG is controversial. In 1994, we reported our initial experience involving 44 patients and have now updated our series in an attempt to further evaluate outcomes. Methods: Between January 1992 and July 2001, 100 consecutive patients underwent reoperative AVR following previous CABG. Forty patients had their initial surgery at the Brigham & Womens Hospital (BWH) and 60 patients had their coronary surgery elsewhere. None of the 40 BWH patients had a mean valve gradient greater than 25 mmHg at the time of CABG. Results: The mean time interval from CABG to AVR for the entire group was 9.0 years (range: 1.4–21 years). Overall operative mortality (OM) was 7% including 5 deaths (10.2%) among 49 patients requiring additional CABG at the time of AVR and 2 deaths (3.9%) among 51 patients without additional coronary artery intervention. This OM rate was a notable decrease from our earlier report of 18.2% (P = 0.07). Furthermore, operative mortality decreased progressively from 15.4% in 1992–1993 to 0% in 2000–2001 (P = NS). Conclusion: The OM of reoperative AVR following CABG has fallen in recent years. Given the relevance of newer techniques and approaches, it may be reasonable to adopt an expectant management approach in patients with asymptomatic mild‐to‐moderate AS (i.e., mean systolic gradient less than 25 mmHg) at the time of CABG. (J Card Surg 2003;18:507‐511)

Mitral Valve Repair in Redo Cardiac Surgery

Abstract  An increasing number of patients are being referred for mitral valve repair in the redo cardiac surgery setting. The most common clinical scenarios involve prior coronary bypass surgery or aortic valve replacement, each presenting special challenges in terms of gaining valve exposure to enable repair while limiting dissection as much as possible. A right anterior thoracotomy approach is preferred in most patients, coupled with hypothermic fibrillatory arrest. A repeat sternotomy may be favored in select circumstances such as when there is a need for bypass grafting or moderate aortic insufficiency is present. Special attention to cannulation techniques, perfusion conditions, valve exposure, and de‐airing maneuvers are all important to ensure good clinical results. Using a tailored approach we have performed mitral valve repair in 22 patients with a patent left internal mammary artery graft following coronary artery bypass grafting between July 1992 and February 2000 with acceptable morbidity and low mortality.

Role of the cryopreserved homograft in isolated elective aortic valve replacement.

In 100 consecutive patients who underwent isolated elective homograft AVR, hospital and 30-day mortality was zero, whereas 12- and 60-month survival was 100% and 98%, respectively. Thus, homograft AVR is a highly safe operation with excellent early and midterm results despite involving root and valve replacement. Given the superior durability in younger patients, this may be the AVR prosthesis of choice for the young (<40 years) to middle-aged (40 to 65 years) patient who cannot commit to lifelong anticoagulation.

Myocardial neutrophil sequestration during reperfusion of the transplanted rabbit heart

BACKGROUND Neutrophils are major participants in myocardial reperfusion injury, but the relationship between ischemic time and the extent of the neutrophil sequestration in heart transplantation has not yet been systematically studied. This study was designed to determine whether increased ischemic time would cause greater neutrophil sequestration during reperfusion of the globally ischemic heart. METHODS Rabbit hearts were arrested with cardioplegia, explanted, and subjected to either 1 or 4 hours of global ischemia at 4 degrees C before being heterotopically transplanted into a recipient rabbits abdomen for reperfusion. Each heart was reperfused for either 4, 8, or 12 hours. Between 3 and 7 hearts were studied (average = 5.8) for each combination of ischemic and reperfusion time (total = 35). A myeloperoxidase (MPO) assay was used to qualify neutrophil content. RESULTS MPO activity (U/g wet weight) was not significantly different at 4, 8, and 12 hours of reperfusion (0.33 +/- 0.05, 0.20 +/- 0.04, 0.26 +/- 0.04: p = 0.13), but was significantly increased at 4 hours compared to 1 hour ischemia (0.34 +/- 0.04 vs 0.19 +/- 0.03: p = 0. 006). Interaction between ischemic and reperfusion times was not significant (p = 0.12). MPO activity was below the measurable threshold in 5 freshly excised control hearts. CONCLUSIONS These results suggest that acute reperfusion injury will be more severe in the hearts subjected to 4 hours ischemia and indicate the need to consider neutrophil-mediated reperfusion injury when addressing cardioprotective interventions for cardiac preservation and reperfusion after transplantation. Neutrophil-mediated reperfusion injury of the rabbit myocardium after heterotopical transplantation is more severe in hearts subjected to 4 hours of ischemia vs 1 hour of ischemia prior to transplantation.