Design and training effects of a physical reality simulator for minimally invasive mitral valve surgery.

OBJECTIVES: Minimally invasive mitral valve surgery (MIMVS) through an endoscopic right minithoracotomy is a well-established yet complex procedure that has a challenging learning curve. We have developed a simulator for MIMVS and evaluated its short- and long-term training effects. METHODS: Trainees without simulator experience or training in MIMVS were divided into 2 groups (10 students and 10 residents) and participated in a 5-day training course after initial instruction. Each trainee performed a ring annuloplasty. Scores were given by a supervisor who assessed 5 skills. The duration of each procedure was also measured. To evaluate the long-term effect of the training course, trainees performed the same procedure 4 weeks after the last session. RESULTS: Trainees in the resident group were significantly older compared to those in the student group and had a mean surgical experience of 4.4 ± 0.78 years standard error of the mean. All other demographic data were similar. Significant learning curves could be achieved in both groups over the course of 5 days with regard to total skill scores and total duration. However, when we compared the learning curves of both groups, no significant difference could be seen. Long-term performance in both groups was still significantly better compared to that in the first training session. CONCLUSIONS: Training with our simulator provided a significant enhancement of a trainee's performance. This learning effect was achieved in both groups and was still evident 4 weeks later. We strongly recommend our simulator for simulation-based surgical education of cardiac surgeons interested in MIMVS.

Beating Heart Versus Arrested Heart Isolated Tricuspid Valve Surgery.

We analyzed the long-term results of two surgical techniques (beating versus non-beating) for isolated tricuspid valve (TV) surgery.The long-term results of 92 consecutive patients who underwent isolated TV surgery were analyzed. We compared patients with beating heart (BH) surgery (n = 48) with patients undergoing arrested heart (AH) surgery (n = 44).BH surgery was more frequently chosen in urgent/emergent operations (P = 0.029) and in redo-operations (P < 0.001). Preoperatively, the rates of renal insufficiency (P = 0.002) and EuroSCORE (P = 0.019) were higher in the BH group than in the AH group. There were no differences in perioperative outcomes and 30-day mortality between the groups. However, freedom from reoperation was significantly lower in the BH group compared to the AH group (P = 0.039). We observed a trend towards lower survival rates at 1, 5, and 10 years in the BH group (77%, 54%, and 41%) compared to those of the AH group (86%, 75%, and 72%, P = 0.062). Multivariate Cox hazard model analysis revealed preoperative heart rhythm (P = 0.014, odds ratio [OR] = 2.296) and EuroSCORE (P = 0.022, OR = 1.049) as independent risk factors for mortality after isolated TV surgery.The superiority of BH surgery over AG surgery was not proven. Surgical intervention should be considered early, since patients with elevated EuroSCORES and arrhythmia have significantly higher mortality rates.

Surgical treatment for isolated tricuspid valve endocarditis- long-term follow-up at a single institution.

BACKGROUND: Systematic long-term data on tricuspid valve (TV) endocarditis are limited. The aim of this study was to investigate the outcome of surgery for isolated TV endocarditis. METHODS AND RESULTS: A total of 637 patients who underwent TV surgery between June 1996 and September 2012 at Hannover Medical School were retrospectively investigated. Of the 637 patients, 33 (14 female, mean age, 49 ± 21 years) underwent isolated TV surgery for endocarditis: biological TV replacement, n=14; mechanical TV replacement, n=4; TV reconstruction, n=15. A total of 28 cases were associated with i.v. drug abuse (n=14) or pacemaker infection (n=14). Staphylococcus (S.) aureus was the most common microorganism detected on preoperative blood culture. Mean follow-up was 6.0 ± 4.1 years (83% completed). Three patients (9%) died during the first 30 postoperative days. Survival at 1, 5 and 10 years was 88%, 73%, and 73%, respectively. Freedom from reoperation was 100%, 95%, and 88%, respectively. During follow-up New York Heart Association class improved significantly, and echocardiography identified remaining TV insufficiency grade ≥ II° only in 2 patients. Statistical analysis identified advanced age, logistic EuroSCORE and positive blood culture for S. aureus as significant risk factors for long-term mortality. CONCLUSIONS: Isolated TV endocarditis is strongly associated with i.v. drug abuse or pacemaker infection. Long-term outcome is acceptable, independent of the surgical procedure.

Pacemaker dependency after isolated aortic valve replacement: do conductance disorders recover over time?

OBJECTIVES: Permanent pacemaker (PPM) implantation is required in 3-8% of all patients undergoing aortic valve replacement (AVR). Our aim was to evaluate long-term PPM dependency and recovery of atrioventricular (AV) conduction disorders during follow-up in these patients. METHODS: Since January 1997, a total of 2106 consecutive patients underwent isolated AVR at our institution. Of these, 138 patients (6.6%, 72 female, median age 71 (37-89) years) developed significant conduction disorders leading to PPM implantation postoperatively. Preoperative ECG showed normal sinus rhythm (n = 64), first degree AV block (n = 19), left bundle branch block (n = 13), right bundle branch block (n = 16), left anterior hemiblock (n = 14) and AV block with ventricular escape rhythm (n = 10). Atrial fibrillation was present in 23 patients. Pacemakers were implanted after a median of 7 (1-30) days following AVR. PPM dependency was analysed by ECG and pacemaker check during follow-up. RESULTS: A total of 45 of 138 patients with postoperative PPM Implantation died during a mean follow-up time of 5.3 ± 4.7 years. A further 9 patients were lost to follow-up. Long-term survivals at 1, 5 and 10 years were 88%, 79% and 59%, respectively. Only 8 (10%) of 84 survivors were no longer pacemaker-dependent. The majority of patients (n = 66, 79%) required permanent ventricular stimulation, and the remaining 10 (13%) showed intermittent stimulation with a mean ventricular stimulation fraction of 73% (22-98%). CONCLUSIONS: The majority of patients do not recover from AV conduction disorders after AVR. Since higher-grade AV blocks expose patients to a high risk of sudden death after surgery, we recommend early implantation of permanent pacemaker.

The first fifty consecutive Bentall operations with a prefabricated tissue-valved aortic conduit: a single-center experience.

BACKGROUND AND AIM OF THE STUDY: Composite replacement is the standard treatment for the repair of aortic aneurysm with aortic valve pathology. With improved long-term durability and no requirement for long-term anticoagulation, tissue-valved conduits have become increasingly popular. Herein are reported the results achieved with 50 consecutive 'Bentall' operations, using the first commercially available prefabricated stentless tissue-valved conduit (Vascutek BioValsalva). METHODS: Between September 2007 and September 2009, a total of 50 patients (10 females, 40 males; mean age 65 +/- 7 years) received a BioValsalva conduit. Concomitant procedures included coronary artery bypass grafting (CABG; n = 15), other valve (n = 5), and aortic arch replacement with circulatory arrest (n = 20; three of these had an additional frozen elephant trunk). Four of the procedures were re-operations. A six-month follow up with echocardiography and clinical examination was completed in 25 patients. RESULTS: The 30-day mortality was 8% (4/50). Three of these patients underwent concomitant procedures. The cardiopulmonary bypass (CPB) and cross-clamp times were 178 +/- 30 min and 106 +/- 7 min, respectively. The triple-layered vascular graft proved to be hemostatic, without suture-line bleeding. Both, the initial and follow up echocardiography showed no valvular insufficiency, with a mean gradient of 13 +/- 5 mmHg. All patients were in NYHA class I-II. CONCLUSION: The BioValsalva prefabricated tissue-valved conduit showed very good early results. The ischemic time required to construct a 'home-made' stentless tissue-valved conduit was eliminated, thus reducing the cross-clamp time. The conduit also offered the hemodynamic advantages of a stentless valve.

Aortic root reoperation: a technical challenge.

BACKGROUND AND AIM OF THE STUDY: It is well known that aortic root re-replacement presents a formidable technical challenge. Thus, the study aim was to describe the authors' experience with this high-risk cohort. METHODS: Between August 1996 and January 2009, a total of 26 patients (mean age 51 years; range: 16-72 years) underwent aortic root re-replacement surgery at the authors' institution. Previous aortic root operations included mechanical valved conduit (n = 9), tissue valved conduit (n = 5), Ross procedure (n = 4), homograft (n = 4), David procedure (n = 2) and Yacoub procedure (n = 2). The indications for surgery included endocarditis (n = 16), Ross procedure failure (n = 4), valve degeneration (n = 3), anastomotic aneurysm (n = 2), and severe valve insufficiency (n = 1). RESULTS: The reoperations performed were classified as follows: aortic homograft (n = 11), mechanical conduit (n = 9), tissue valved conduit (n = 4) and David procedure (n = 2). The mean cardiopulmonary bypass time was 219 min (range: 101-398 min), and the mean cross-clamp time 142 min (range: 89-253 min). The mean ICU stay was 8 days (range: 1-45 days), and the mean hospital stay 20 days (range: 3-64 days). Four rethoracotomies were performed for postoperative bleeding or tamponade (14%). Two patients (8%) died within 30 days of surgery, and three (12%) required pacemaker implantation due to atrioventricular block (grade III). CONCLUSION: Aortic root reoperation, even in the setting of endocarditis, can be carried out with excellent results. The major goals of this concept include a clinical examination and preoperative diagnosis, in addition to computed tomography to identify possible pitfalls during re-sternotomy. Care must also be taken to provide adequate myocardial and organ protection, by utilizing blood cardioplegia and individual selective perfusion techniques.