Impact of progressive sinotubular junction dilatation on valve competence of the 3F Aortic and Sorin Solo stentless bioprosthetic heart valves.

OBJECTIVE: The use of stentless bioprostheses for aortic valve replacement provides excellent haemodynamics; however, these valves bear the potential risk of progressive regurgitation over time. To overcome this disadvantage, a new generation of pericardial stentless prostheses has been developed. This study aims to assess the tolerance of such bioprotheses against progressive sinotubular junction dilatation. METHODS: Five specimens of both the 3F Aortic and Sorin Solo stentless bioprotheses (diameter 25 mm) were investigated in a pulsatile flow simulator incorporating a device for gradual expansion of the sinotubular junction diameter. Closing characteristics were obtained by high-speed video imaging and the corresponding regurgitations were determined by ultrasonic flow measurements. The diameters D(R), at which primary distinct regurgitation occurs, were correlated to the original diameters D(A) and expressed as percentage values. RESULTS: The highest tolerance against sinotubular junction dilatation was found for the 3F Aortic (156+/-5%) compared to the Sorin Solo (145+/-6%, p=0.0127) bioprothesis. Visualisation of the valves revealed strong leaflet folding at labelled diameter, similar in both valve types. CONCLUSIONS: New-generation pericardial stentless bioprotheses provide favourable adaptability to sinotubular junction dilatation, more pronounced for the 3F prosthesis. Whether undue leaflet folding caused by the redundant tissue influences long-term function remains to be established.

Strategies for the reduction of cerebral microembolism during transmyocardial laser revascularization.

BACKGROUND AND OBJECTIVES: During transmyocardial laser revascularization (TMLR), multiple microembolic signals (MES) can be detected in cerebral arteries. We sought to characterize composition and clinical relevance of these MES and to evaluate strategies to reduce cerebral microembolization during TMLR. STUDY DESIGN/MATERIALS AND METHODS: TMLR was performed in pigs. Laser energy was set to 4-10 J (group A) or 80 J (group B). Oxygen concentration was varied between 21 and 100%. MES were recorded in the ophthalmic artery. Brain and spinal cord were investigated histologically after 10 days. RESULTS: More MES could be detected during high- compared to low-energy laser procedures. Ventilation with 100% oxygen reduced the number of MES. No lesions were found on histology. CONCLUSIONS: The number of MES depends on the laser energy. Laser-induces cavitation-effects lead to an additional release of nitrogen bubbles. Thus, the microembolic load can be reduced by ventilation with 100% oxygen and by decreasing the laser energy.

High incidence of sudden death late after anterior LV-aneurysm repair.

OBJECTIVES: Sudden death due to ventricular arrhythmias occurs frequently among patients with dilated cardiomyopathy and congestive heart failure (CHF). In patients with left ventricular (LV) aneurysms, LV-aneurysm repair (LVAR) reduces LV-size and ameliorates symptoms of CHF, but the incidence of late sudden death is unknown, especially after LVAR without concomitant anti-arrhythmic therapy. METHODS: Between June 1993 and June 1999, 147 patients (70% males; 62+/-9 years) with CHF (median: NYHA III) due to anterior LV-aneurysms underwent LVAR. None of the patients underwent anti-arrhythmic surgical procedures concomitant to LVAR. Ninety percent of the patients had additional myocardial revascularization. Hospital records and laevocardiograms were reviewed, and follow-up information was obtained. RESULTS: In-hospital mortality was 4.1% (n=6). The median follow-up was 3.7 years (0.1-73.4 months; overall 462 patient-years). At follow-up, the patients had significantly less symptoms than preoperatively (median: NYHA II, P<0.001). Nineteen patients had died (5-year survival rate 78%). Of these late deaths, 84% (n=16) were cardiac-related, among which sudden death was most frequent (n=7). Predictors of sudden death were a bypass graft to the right coronary artery (P=0.0100), ventricular tachyarrhythmias early postoperatively (P=0.0315), and cross-clamp time (P=0.0496). CONCLUSIONS: Although the survival and functional state of most patients were good after LVAR without concomitant anti-arrhythmic surgery, we observed a high incidence of late sudden death, which was-among others-significantly associated with postoperative ventricular tachyarrhythmias. To further improve outcomes, intra- and postoperative anti-arrhythmic therapy is advisable in patients undergoing LVAR.

Results of endoaneurysmorrhaphy: does the location of the aneurysm matter?

Endoaneurysmorrhaphy is mostly performed on anterior-septal left ventricular (LV) aneurysms. It may also be applied to posterior aneurysms, which is technically more challenging. Whether the surgical risk is the same, irrespective of the location of the aneurysm, has not been studied before. We reviewed our experience with 158 patients (62+/-9 years, 72% male) undergoing endoaneurysmorrhaphy. Eleven patients (7%) had posterior LV aneurysms. Perioperative mortality was 5.7%. Of all preoperative and surgical variables tested, the presence of a posterior LV aneurysm (p=0.017), concomitant mitral valve surgery (p=0.008) and duration of extracorporal circulation (p=0.001) were significantly associated with higher perioperative mortality. However, patients with posterior LV aneurysms had more severe heart failure (p=0.0061) and a higher LV end diastolic volume index (138+/-38 vs. 102+/-41 ml/kg body weight; p=0.040) than patients with antero-septal LV aneurysms. Further studies are needed to determine whether the location of the aneurysm is a risk factor for mortality irrespective of the clinical presentation.

Up to 7 years' experience with valve-sparing aortic root remodeling/reimplantation for acute type A dissection.

BACKGROUND: Aortic valve-sparing operations for acute type A dissection are appealing and innovative but less well defined surgical techniques requiring further evaluation. METHODS: We reviewed all consecutive patients with acute type A dissection who underwent either the remodeling (group 1, n = 21) or the reimplantation valve-sparing technique (group 2, n = 15) since October 1994. Patients were followed up clinically and echocardiographically for as long as 41.3 months (group 1) and 87 months (group 2). RESULTS: Hospital mortality was 19% (n = 4) for group 1 and 20% (n = 3) for group 2. Permanent new neurologic symptomatology occurred in 1 patient (3.6%). Three patients in group 1 required reoperation owing to redissection. No patient had an aortic insufficiency of more than grade 1. No late neurologic or thrombembolic events occurred. There was no statistically significant difference between both groups with respect to clinical and hemodynamic data. CONCLUSIONS: Remodeling and reimplantation aortic valve-preserving operations in acute type A dissection can be performed with adequate perioperative risk and excellent midterm aortic valve function. We found no evidence of one technique being superior to the other, however durability of the remodeling technique needs critical consideration especially in Marfan syndrome and when glue is used.

Lung protection during total cardiopulmonary bypass by isolated lung perfusion: preliminary results of a novel perfusion strategy.

BACKGROUND: The present pilot study was conducted to evaluate the effect of isolated short-term lung perfusion during cardiopulmonary bypass (CPB) on inflammatory response and oxygenation. METHODS: A total of 24 patients undergoing elective cardiac surgery with routine CPB were prospectively assigned to three groups. Group I (n = 7), control subjects receiving neither lung perfusion nor ultrafiltration; group II (n = 9), patients undergoing lung perfusion; and group III (n = 8), patients undergoing lung perfusion plus ultrafiltration. Lung perfusion consisted of single-shot hypothermic pulmonary artery perfusion with oxygenated blood. Proteins indicative of leukocyte activation and lung injury were measured in plasma and bronchoalveolar lavage fluid (BALF). The alveolar-arterial oxygen gradient (A-aDO2) and the oxygenation index (PO2/FiO2) were also determined. RESULTS: Oxygenation values were best preserved in group III, followed by group II. After CPB, elastase-alpha1-proteinase inhibitor complex had increased in plasma in all groups; in BALF it increased in groups I and II, but not in group III. Alpha2-macroglobulin increased significantly in BALF in group I but not in groups II and III. CONCLUSIONS: These preliminary results provide some evidence that single-shot hypothermic lung perfusion with oxygenated blood at the beginning of CPB may have a protective effect on the lungs, especially when combined with ultrafiltration.