Myocardial metabolism before and after valve replacement for aortic stenosis

AIM: Post ischemic disturbances of myocardial metabolism that may contribute to postoperative heart failure and are accessible to metabolic treatment have been identified early after coronary surgery. Knowledge derived from these studies may not be applicable to other patient groups. Therefore we studied myocardial energy metabolism in patients operated for isolated aortic stenosis. METHODS: Twenty patients undergoing isolated aortic valve replacement (AVR) because of aortic stenosis without significant regurgitation were studied before and immediately after surgery. Myocardial uptake of oxygen and energy substrates was assessed with coronary sinus catheter technique. RESULTS: Free fatty acids (FFA) were the main source of myocardial energy before and after AVR. A significant uptake of lactate was only recorded preoperatively. A significant uptake of glutamate of the same magnitude as previously described in coronary patients was found pre- and postoperatively. Postoperatively a relative decrease of myocardial oxygen extraction ratio (P<0.001) and oxygen consumption (P=0.14) by approximately 20% was observed. CONCLUSION: Preoperative and postoperative metabolic adaptation with substantial uptake of glutamate, previously claimed to be due to chronic or repetitive ischemia, was demonstrated. The results indicate that oxidative metabolism had not fully recovered when the procedure was completed. However, the potentially unfavorable postoperative metabolic state with predominant reliance on FFA as energy source was out-balanced by the unloading effect of AVR with a reduction in myocardial oxygen extraction.     

Sutureless versus conventional bioprostheses for aortic valve replacement in severe symptomatic aortic valve stenosis

ObjectiveSutureless aortic valves are a novel option for aortic valve replacement. We sought to demonstrate noninferiority of sutureless versus standard bioprostheses in severe symptomatic aortic stenosis.MethodsThe Perceval Sutureless Implant Versus Standard-Aortic Valve Replacement is a prospective, randomized, adaptive, open-label trial. Patients were randomized (March 2016 to September 2018) to aortic valve replacement with a sutureless or stented valve using conventional or minimally invasive approach. Primary outcome was freedom from major adverse cerebral and cardiovascular events (composite of all-cause death, myocardial infarction, stroke, or valve reintervention) at 1 year.ResultsAt 47 centers (12 countries), 910 patients were randomized to sutureless (n = 453) or conventional stented (n = 457) valves; mean ages were 75.4 ± 5.6 and 75.0 ± 6.1 years, and 50.1% and 44.9% were female, respectively. Mean ± standard deviation Society of Thoracic Surgeons scores were 2.4 ± 1.7 and 2.1 ± 1.3, and a ministernotomy approach was used in 50.4% and 47.3%, respectively. Concomitant procedures were performed with similar rates in both groups. Noninferiority was demonstrated for major adverse cerebral and cardiovascular events at 1 year, whereas aortic valve hemodynamics improved equally in both groups. Use of sutureless valves significantly reduced surgical times (mean extracorporeal circulation times: 71.0 ± 34.1 minutes vs 87.8 ± 33.9 minutes; mean crossclamp times: 48.5 ± 24.7 vs 65.2 ± 23.6; both P < .0001), but resulted in a higher rate of pacemaker implantation (11.1% vs 3.6% at 1 year). Incidences of perivalvular and central leak were similar.ConclusionsSutureless valves were noninferior to stented valves with respect to major adverse cerebral and cardiovascular events at 1 year in patients undergoing aortic valve replacement (alone or with coronary artery bypass grafting). This suggests that sutureless valves should be considered as part of a comprehensive valve program.     

Ascending-to-descending aortic bypass and aortic valve replacement for concomitant severe aortic coarctation and aortic stenosis

We present a 33-year-old male with severe, symptomatic aortic coarctation and aortic stenosis assessed on a humanitarian medical mission to a developing country. Contemplating limited time and available resources, we performed a simultaneous single-stage approach with ascending-to-descending aortic bypass with a reinforced gortex graft and concomitant aortic valve replacement through a median sternotomy. The patient had an uneventful postoperative convalescence and was discharged on postoperative day 5. At 1-year follow-up, he was asymptomatic and doing well with good blood pressure control and complete equalization of upper and lower limb blood pressure measurements. Computed tomography and transthoracic echocardiography demonstrated a widely patent ascending-to-descending aortic bypass graft and a normally functioning prosthetic aortic valve, respectively. In developing countries where health care resources are limited, a combined approach with an extra-anatomic, thoracic aortic bypass, and aortic valve replacement resulted in good early and 1-year outcomes. This procedure may represent the most effective surgical option for patients with concomitant aortic coarctation and aortic stenosis.     

Results of prosthetic valve replacement for aortic stenosis

Background: Aortic valve replacement with mechanical valves is associated with a small but constant risk of valve thrombosis and thromboembolic and hemorrhagic complications. The surgical outcome of patients with Aortic Stenosis who had aortic valve replacement with mechanical valves is reported here. Methods: Between January 1990 and October 1999, 275 patients underwent prosthetic valve replacement for isolated aortic stenosis. The age ranged between 13 years and 75 years and 230 were males. The cause of aortic stenosis was rheumatic in 185 patients (67.3%), followed by bicuspid aortic valve in 75 patients (27.3%) and degenerative in 15 patients (5.4%). Results: The early mortality was 1.5%. The follow up was 96% complete and ranged from 1 to 104 months (mean 54±24.5months). Six patients (2.2%) developed prosthetic valve endocarditis. Paravalvular leak occurred in 3 (0.9%) patients. Valve thrombosis occurred in 10 patients (1.0% per patient year). The actuarial survival was 81±7% at 5 years and 64±13% at 8 years. Event free survival was 40±14% at 8 years. Conclusion: With current operative techniques and myocardial preservation aortic stenosis patients are at low risk for surgery. However, long term survival is limited due to prosthesis related complications.     

The optimal timing of aortic valve replacement in elderly patients with severe aortic stenosis

Purpose

The elderly population with severe aortic stenosis (AS) requiring aortic valve replacement (AVR) is increasing. The optimal timing of AVR in these patients has been under discussion.

Methods

We retrospectively reviewed the data from severe AS patients (n = 84) who underwent AVR with/without concomitant procedures from 2005 to 2010. The symptom status, preoperative data, operative outcome, late survival and freedom from cardiac events were compared between elderly patients (age ≥80 years [n = 31]) and younger patients (age <80 years [n = 53]).

Results

The operative mortality in elderly patients (3.2 %) and younger patients (3.8 %) was comparable. The symptoms in elderly patients were more severe and hospitalized heart failure (HF) was more frequently noted as the primary symptom (p = 0.017). Patients with and without hospitalized HF differed significantly in late survival and freedom from cardiac events (p = 0.001), but advanced age had no significant effect. The results of a Cox proportional hazards analysis revealed that hospitalized HF was a significant predictor for cardiac events after AVR, irrespective of age (hazard ratio 6.93, 95 % confidence interval 1.83–26.26, p < 0.004).

Conclusions

In elderly patients with severe AS, surgery should be recommended even in the presence of minimal symptoms and should be performed before the onset of life-threatening HF.     

经导管主动脉瓣植入术治疗重度主动脉瓣狭窄

目的 观察经导管主动脉瓣植入术（TAVI）治疗重度主动脉瓣狭窄（AS）的效果。方法 回顾性收集18例接受TAVI的重度AS患者,记录TAVI即刻成功率,观察治疗过程中及治疗后相关并发症;随访记录治疗后1、3个月瓣膜功能及心血管事件。结果 18例实施TAVI成功。对3例AS合并冠心病患者行一站式TAVI+经皮冠状动脉介入治疗,对2例冠状动脉阻塞高风险患者通过“烟囱”或“开窗”技术加以预保护。1例顽固性心力衰竭患者接受体外膜氧合器辅助下TAVI;1例尿毒症患者于TAVI前、后接受血液透析。TAVI即刻成功率100%（18/18）。TAVI过程中1例发生心脏压塞而转外科治疗;1例因中度瓣周漏而植入另1枚瓣膜。治疗后3例存在轻度瓣周漏,1例因三度房室传导阻滞而植入永久性心脏起搏器。未见严重并发症。治疗后即刻及1、3个月,超声心动图显示主动脉瓣口流速［（203.47±70.65）、（219.64±67.49）、278.00（188.50,289.00）cm/s］和跨瓣压差［（17.16±14.05）、0（0,20.50）、12.00（0,32.50）mmHg］均较治疗前［470.50（428.75,553.25）cm/s、79.50（53.25,112.50）mmHg］降低（P均＜0.05）。治疗后3个月内无死亡、卒中、急性冠脉综合征及新发房颤等严重心血管事件发生。结论 TAVI治疗重度AS安全,且短期疗效好。     

Two Surgical cases of right parasternal minimal incision for aortic valve replacement

Although median sternotomy has been used as a good approach to all cardiac valves and coronary arteries, advantages of the minimal invasive cardiac operation have been reported recently. We employed the right parasternal minial incision, reported by Cosgrove et al. for two cases of aortic valve replacement. In the first case, we were able to get a good operation field and easily implanted a mechanical prosthesis. In contrast, we had some difficulties with the second case where in addition to the third and fourth cartilages, a second cartilage resection was necessary because the aortic root lay at a cephalic level. Moreover, the operation field was restricted because we left several rib cartilages to preserve the right internal thoracic artery. The cannula had to be inserted via the right atrium as we failed to insert it in the right femoral vein, and the aortic root deviated more medially than usual. From these experiences, it is important to check the position of aortic root, and if the cannula cannot be inserted in the femoral vein, cannulation via the right atrium can ve utilized in the minimal invasive cardiac operation. (J Jpn Assn Thorac Surg 1998; 46: 243-247)     

Surgical aortic valve replacement for stenosis of TAVI device

We here report the case of a stenosis of the CoreValve^® system due to reduced mobility of prosthesis cusps for which a surgical replacement of the aortic valve was proposed. The exact mechanism leading to this impaired mobility of the leaflets is yet to be determined. We also underline the fact a transcatheter aortic valve implantation (TAVI) device can be replaced by a surgical replacement without excessive operative risks despite the patient being initially considered as high-risk.     

Combined emergency abdominal aortic aneurysm repair and valve replacement in a patient with severe aortic stenosis

Simultaneous open surgery has been advocated in the elective management of abdominal aortic aneurysm patients with significant ischemic heart disease, as staged procedures risk worsening myocardial ischemia or aortic rupture, depending on which is the first intervention. The argument for combined aneurysm and valve repair is less established. We describe the case of a 70-year-old female who while awaiting aortic valve replacement suffered rupture of an abdominal aortic aneurysm. The patient was successfully managed with emergency combined open abdominal aortic aneurysm repair and open aortic valve replacement. We would advocate that such a strategy be considered as a salvage technique in similarly difficult management dilemmas.     

Aortic valve replacement for aortic stenosis with a small mechanical prosthetic valve

BACKGROUND: Although aortic valve replacement (AVR) is the only effective treatment for patients with aortic stenosis (AS), it is recognized that the use of small prosthetic valves due to a small aortic root often affects postoperative course after AVR. The aim of this study was to determine whether the use of small prosthetic valves was a risk factor of AVR for AS. METHODS: We compared various perioperative factors and operative outcomes between patients with a small mechanical prosthetic valve (small group) and patients with a large mechanical prosthetic valve (large group). RESULTS: Early mortality was 0% in each group and the 5-year mortality was 25% in the small group and 10% in the large group. There were no significant differences in perioperative factors between the two groups. The small group patients were significantly older and smaller compared to the large group patients. The valve size was significantly correlated with age and BSA. CONCLUSIONS: The use of small mechanical prostheses was not a risk factor of AVR for AS when it was proportionate to the BSA even for elderly patients. AVR using a small mechanical prosthetic valve may be performed with good results in the short- and long-term.