Background: To predict the occurrence of valve prosthesis-patient mismatch (VP-PM) after aortic valve replacement (AVR), the surgeon needs to estimate the postoperative effective orifice area index (EOAI). Aim: To compare different methods of predicting VP-PM. Methods: The effective orifice area (EOA) of 383 patients who had undergone AVR between July 2000 and January 2005 with various aortic valve prostheses was obtained echocardiographically 6 months after the operation. We tested the efficacy of (1) EOAI calculated from the echo data obtained in our own laboratory, (2) indexed geometric orifice area, (3) EOAI estimated from charts provided by prosthesis manufacturers (which are based either on in vitro or on echo data) and (4) EOAI estimated from reference echo data published in the literature to predict VP-PM. Results: Sensitivity and specificity to predict VP-PM were 53% and 83% (method 1), 80% and 53% (charts based on echo data, parts of method 3) and 71% and 67% (method 4) using reference data derived from echocardiographic examinations. The sensitivity of method 2 and of charts based on in vitro data (parts of method 3) to predict VP-PM was 0-17%. The incidence of severe VP-PM could be reduced from 8.7% to 0.8% after the introduction of the systematic estimation of the EOAI at the time of operation (p = 0.003, method 1). Conclusions: The best method of predicting VP-PM is the use of mean (SD) EOAs derived from echocardiographic examinations, whereas the use of in vitro data or the geometric orifice area is unreliable. After the surgeon's anticipation of VP-PM prior to AVR, the incidence of VP-PM could be reduced.

In patients with an aortic annulus of 18 to 20 mm in diameter, hemodynamic performance is independent of the implanted stented valve type and the annular position. Root enlargement or stentless valves may be beneficial alternatives. Patients with annulus diameter 21 to 23 mm benefit from the Magna in complete supra-annular position leading to superior hemodynamic results.

Background There has been ongoing controversy as to whether prosthesisepatient mismatch (PPM, defined as indexed effective orifice area (EOAI) <0.85 m 2 /cm 2 ) influences mortality after aortic valve replacement (AVR). In most studies, PPM is anticipated by reference tables based on mean EOAs as opposed to individual assessment. These reference values may not reflect the actual in vivo EOAI and hence, the presence or absence of PPM may be based on false assumptions. Objective To assess the impact of small prosthesis EOA on survival after aortic valve replacement AVR. Methods 645 patients had undergone an AVR between 2000 and 2007 entered the study. All patients underwent transthoracic echocardiography for determination of the actual EOAI within 6 months postoperatively. In order to predict time from surgery to death a proportional hazards model for competing risks (cardiac death vs death from other causes) was used. EOAI was entered as a continuous variable. Results PPM occurred in 40% of the patients. After a median follow-up of 2.35 years, 92.1% of the patients were alive. The final Cox regression model showed a significantly increased risk for cardiac death among patients with a smaller EOAI (HR¼0.32, p¼0.022). The effect of EOAI on the 2e5 year mortality risk was demonstrated by risk plots. Conclusions In contrast to previous studies these EOAI values were obtained through postoperative echocardiography, substantially improving the accuracy of measurement, and the EOAI was modelled as a continuous variable. There was a significantly improved survival for larger EOAIs following AVR. Strategies to avoid PPM should become paramount during AVR.

The Perimount Magna had a significantly reduced incidence of patient-prosthesis mismatch and superior hemodynamics compared to the standard Perimount.

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Acute mesenteric ischemia is a rare but severe complication after open heart surgery. Its incidence (0.2-0.4%) is quite low, but mortality rates are ranging between 70% and 100%. From October 1992 to December 1996, 4,640 patients underwent open heart surgery with cardiopulmonary bypass: 74.6% coronary artery bypass graft (CABG) operations, 23.2% valve replacement including aortic repairs, and 2.2% corrections of congenital heart diseases or tumors of the heart. The overall mortality rate (30 days) was 3.4%, and after CABG, 2.9%. Twelve patients (0.26%), following CABG (one combined with aortic valve replacement, one with mitral reconstruction, and one with carotid disobliteration) developed signs of acute mesenteric ischemia in the early postoperative period (day 1 to 5). In all patients various abdominal symptoms, leukocytosis, acidosis, hyperlactatemia, hyperosmolality, renal failure, and, finally, hemodynamic instability were observed. Eleven patients underwent emergency laparotomy. Mesenteric angiography was done if possible in still stable patients (n=7); it showed severe stenosis or occlusion prior to the operation in each case. Other diagnostic methods were not reliable. In six patients (55%) during the first look, extensive bowel necrosis was found and in five patients an ischemic intestine but no necrosis was detected. Of these, three patients were affected by extensive bowel gangrene at the second look. In the fourth patient a disseminated peripheral ischemia of the entire small intestine was found intraoperatively. After mechanical release and stimulation normal bowel function could be reestablished. One patient underwent percutaneous transluminal angioplasty prior to the laparotomy. Bowel perfusion was still deteriorated but no necrosis was found intraoperatively. These patients were the only survivors in the investigated group; 10 of 12 patients (83.3%) died in the early postoperative period (day 1 to day 6). Predisposing factors for mesenteric ischemia are: arteriosclerotic patients after CABG (100%), age >70 years (91.7%), hyperosmotic dehydration (100%), and cardiac ischemia in 25%. Mesenteric ischemia is a fatal complication with high mortality rates after open heart surgery, especially in older, dehydrated patients with generalized atherosclerotic vessel disease. As the acute mesenteric ischemia usually starts during anesthesia or in the early postoperative period, setting of immediate diagnosis is very difficult. With the occurrence of typical symptoms diagnostic and therapeutic procedures (angiography and laparotomy) must be done very urgently owing to the life-threatening mesenteric process. When mesenteric gangrene already has taken place, the prognosis is very poor, despite extensive resection. Prevention can be exercised by avoiding perioperative hyperosmotic dehydration of patients at high risk.

The present study reveals a significant impact of PPM on physical capacity, measured by exercise testing, in patients after AVR. Although other factors such as training status and comorbidity (for example, concomitant coronary revascularisation) also influence the achievement of higher exercise levels, our data strengthen the hypothesis that the avoidance of PPM could result in better exercise capacity for patients after AVR.