Impact of endoluminal stenting for aortic surgery

The advent of stents has profoundly changed percutaneous transluminal coronary angioplasty (PTCA), peripheral transluminal artery angioplasty (PTA), and treatment strategies of numerous other problems. Similar developments can be observed for stent applications in peripheral vascular lesions, cerebro-vascular disease, and many other fields. With the advent of covered stent-grafts, aneurysm surgery, has been put up for competitive treatment approaches. Such new approaches are perceived as less invasive, and draw significant attention. Endovsacular aneurysm repair (EVAR) is here to stay. In addition new developments are coming in many ways and stent derived devices can by now be found everywhere in the cardio-vascular system. This includes stenosed vessels, aneurysmal vessels, diseased valves, all sorts of congenital heart defects, and even cardiopulmonary bypass. The key technologies and know-how for EVAR are available or can be made available in most cardio-vascular surgical units. Special interest in this field (clinical and/or experimental) can enhance recruitment of patients. The opposite is also tru

Atrial fibrillation and minimally invasive coronary artery bypass grafting: Risk factor analysis

Atrial fibrillation (AF) is a frequent arrhythmia after conventional coronary artery bypass grafting. With the advent of minimally invasive technique for left internal mammary artery-left anterior descending coronary artery (LIMA-LAD) grafting, we analyzed the incidence and the risk factors of postoperative AF in this patient population. This prospective study involves all patients undergoing isolated LIMA-LAD grafting with minimally invasive technique between January 1994 and June 2000. Twenty-four possible risk factors for postoperative AF were entered into univariate and multivariate logistic regression analyses. Postoperative AF occurred in 21 of the 90 patients (23.3%) analyzed. Double- or triple-vessel disease was present in 12/90 patients (13.3%). On univariate analysis, right coronary artery disease (p<0.01), age (p=0.01), and diabetes (p=0.04) were found to be risk factors for AF. On multivariate analysis, right coronary artery disease was identified as the sole significant risk factor (p=0.02). In this patient population, the incidence of AF after minimally invasive coronary artery bypass is in the range of that reported for conventional coronary artery bypass grafting. Right coronary artery disease was found to be an independent predictor, and this may be related to the fact that in this patient population the diseased right coronary artery was not revascularized at the time of the surgical procedure. For the same reason, this risk factor may find a broader application to noncardiac thoracic surger

Acute ascending aortic dissection complicating open heart surgery: cerebral perfusion defines the outcome

Objective: This retrospective study was designed to assess the risks of acute ascending aorta dissection (AAD) as a rare but potentially fatal complication of open heart surgery. Method: Among 8624 cardiac surgical procedures under cardiopulmonary bypass (CPB) and cardioplegic myocardial protection from 1978 to 1997, 10 patients (0.12%) presented with a secondary or so called ‘iatrogenic' AAD. There were seven men and three women, mean age 64±9 years, ranging from 47 to 79. The original procedures involved five coronary artery bypass grafts (CABG), one repeat CABG, one aortic valve replacement (AVR), one AVR and CABG, one mitral valvuloplasty (MVP) and CABG and one ascending aorta replacement. We retrospectively analyzed their hospital records. Results: Group I consisted of seven patients with AAD intraoperatively and group II consisted of three patients who developed acute AAD 8-32 days after cardiac surgery. In group I, treatment consisted of the original procedure, plus grafting of the ascending aorta in six patients and closed plication and aortic wrapping in one. In group II, two patients received a dacron graft and one patient developed lethal tamponnade due to aortic rupture before surgery. Postoperatively, six patients responded well and three died (33%), two patients from group I on the 2nd postoperative day with severe post-anoxic encephalopathy, and one from group II with severe peroperative cardiogenic shock. Conclusion: Preventing AAD with the appropriate means remains standard practice in cardiac surgery. If AAD occurs, it requires prompt diagnosis and interposition graft to allow a better prognosis. Intraoperative AAD happens at the beginning of CPB jeopardizing perfusion of the supra-aortic arterie

Primary isolated aortic valve surgery in octogenarians

Objectives: We reviewed our surgery registry, to identify predictive risk factors for operative results, and to analyse the long-term survival outcome in octogenarians operated for primary isolated aortic valve replacement (AVR). Methods: A total of 124 consecutive octogenarians underwent open AVR from January 1990 to December 2005. Combined procedures and redo surgery were excluded. Selected variables were studied as risk factors for hospital mortality and early neurological events. A follow-up (FU; mean FU time: 77 months) was obtained (90% complete), and Kaplan-Meier plots were used to determine survival rates. Results: The mean age was 82±2.2 (range: 80-90 years; 63% females). Of the group, four patients (3%) required urgent procedures, 10 (8%) had a previous myocardial infarction, six (5%) had a previous coronary angioplasty and stenting, 13 patients (10%) suffered from angina and 59 (48%) were in the New York Heart Association (NYHA) class III-IV. We identified 114 (92%) degenerative stenosis, six (5%) post-rheumatic stenosis and four (3%) active endocarditis. The predicted mortality calculated by logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 12.6±5.7%, and the observed hospital mortality was 5.6%. Causes of death included severe cardiac failure (four patients), multi-organ failure (two) and sepsis (one). Complications were transitory neurological events in three patients (2%), short-term haemodialysis in three (2%), atrial fibrillation in 60 (48%) and six patients were re-operated for bleeding. Atrio-ventricular block, myocardial infarction or permanent stroke was not detected. The age at surgery and the postoperative renal failure were predictors for hospital mortality (p value ≪0.05), whereas we did not find predictors for neurological events. The mean FU time was 77 months (6.5 years) and the mean age of surviving patients was 87±4 years (81-95 years). The actuarial survival estimates at 5 and 10 years were 88% and 50%, respectively. Conclusions: Our experience shows good short-term results after primary isolated standard AVR in patients more than 80 years of age. The FU suggests that aortic valve surgery in octogenarians guarantees satisfactory long-term survival rates and a good quality of life, free from cardiac re-operations. In the era of catheter-based aortic valve implantation, open-heart surgery for AVR remains the standard of care for healthy octogenarian

Use of a biophysical model of atrial fibrillation in the interpretation of the outcome of surgical ablation procedures

Objective: To determine the adequacy of ‘in silico' biophysical models of atrial fibrillation (AF) in the design of different ablation line patterns. Background: Permanent AF is a severe medical problem for which (surgical) ablation is a possible treatment. The ideal ablation pattern remains to be defined. Methods: Forty-six consecutive adult patients with symptomatic permanent drug refractory AF underwent mitral surgery combined with non-transmural, (n=20) and transmural (n=26) radiofrequency Minimaze. The fraction of ‘in vivo' conversions to sinus rhythm (SR) in both groups was compared with the performance of the fraction of ‘in silico' conversions observed in a biophysical model of permanent AF. The simulations allowed us to study the effectiveness of incomplete and complete ablation patterns. A simulated, complete, transmural Maze III ablation pattern was applied to 118 different episodes of simulated AF set-up in the model and its effectiveness was compared with the clinical results reported by Cox. Results: The fraction of conversions to SR was 92% ‘in vivo' and 88% ‘in silico' (p=ns) for transmural/complete ablations, 60% respectively 65% for non-transmural/incomplete Minimaze (p=ns) and 98% respectively 100% for Maze III ablations (p=ns). The fraction of conversions to SR ‘in silico' correlated with the rates ‘in vivo' (r2=0.973). Conclusions: The fraction of conversions to SR observed in the model closely corresponded to the conversion rate to SR post-surgery. This suggests that the model provides an additional, non-invasive tool for optimizing ablation line patterns for treating permanent A

Aorto-subclavian thromboembolism: a rare complication associated with moderate ovarian hyperstimulation syndrome

The case of an arterial aorto-subclavian thromboembolism associated with a moderate ovarian hyperstimulation syndrome (OHSS) and following ovulation induction for in-vitro fertilization in a young woman is reported. Because of the lack of response to systemic thrombolysis, a left postero-lateral thoracotomy was performed on day 8 after embryo transfer. A fibrinocruoric embolus situated at the junction of the left subclavian artery from the aorta was removed through a left subclavian arteriotomy. The distal axillary embolus was removed by a retrograde balloon catheter embolectomy. A moderate OHSS was observed. The ovarian stimulation and OHSS-related risks of thromboembolism are discussed. We conclude that, in the absence of risk factors, counselling about possible complications resulting from stimulation must be emphasize

A biophysical model of atrial fibrillation to define the appropriate ablation pattern in modified maze

Objective: The surgical Maze III procedure remains the gold standard in treating atrial fibrillation (AF); however due to clinical difficulties and higher risks, less invasive ablation alternatives are clinically investigated. The present study aims to define more efficient ablation patterns of the modified maze procedure using a biophysical model of human atria with chronic AF. Methods: A three-dimensional model of human atria was developed using both MRI-imaging and a one-layer cellular model reproducing experimentally observed atrial cellular properties. Sustained AF could be induced by a burst-pacing protocol. Ablation lines were implemented in rendering the cardiac cells non-conductive, mimicking transmural lines. Lines were progressively implemented respectively around pulmonary veins (PV), left atrial appendage (LAA), left atrial isthmus (LAI), cavo-tricuspid isthmus (CTI), and intercaval lines (SIVC) in the computer model, defining the following patterns: P1=PV, P2=P1+LAA, P3=P2+LAI, P4=P3+CTI, P5=P3+SIVC, P6=P5+CTI. Forty simulations were done for each pattern and proportion of sinus rhythm (SR) conversion and time-to-AF termination (TAFT) were assessed. Results: The most efficient patterns are P5, P6, and Maze III with 100% success. The main difference is expressed in decreasing mean TAFT with a correlation coefficient R=−0.8. There is an inflexion point for 100% success rate at a 7.5s TAFT, meaning that no additional line is mandatory beyond pattern P5. Conclusions: Our biophysical model suggests that Maze III could be simplified in his right atrial pattern to a single line joining both vena cavae. This has to be confirmed in clinical setting

Long-term outcome after mitral valve repair: a risk factor analysis

Objective: Mitral valve repair is the gold standard to restore mitral valve function and is now known to have good long-term outcome. In order to help perioperative decision making, we analyzed our collective to find independent risk factors affecting their outcome. Methods: We retrospectively studied our first 175 consecutive adult patients (mean age: 64±10.4 years; 113 males) who underwent primary mitral valve repair associated with any other cardiac procedures between January 1986 and December 1998. Risk factors influencing reoperations and late survival were plotted in a uni- and multivariate analyses. Results: Operative mortality was 3.4% (6 deaths, 0-22nd postoperative day (POD)). Late mortality was 9.1% (16 deaths, 3rd-125th POM). Reoperation was required in five patients. Kaplan-Meier actuarial analysis demonstrated a 96±1% 1-year survival, 88±3% 5-year survival and a 69±8% 10-year survival. Freedom from reoperations was 99% at 1 year after repair, 97±2% after 5 years and 88±6% after 10 years. Multivariate analysis demonstrated that residual NYHA class III and IV (p=0.001, RR 4.55, 95% CI: 1.85-14.29), poor preoperative ejection fraction (p=0.013, RR 1.09, 95% CI: 1.02-1.18), functional MR (p=0.018, RR 4.17, 95% CI: 1.32-16.67), and ischemic MR (p=0.049, RR 3.13, 95% CI: 1.01-10.0) were all independent predictors of late death. Persistent mitral regurgitation at seventh POD (p=0.005, RR 4.55, 95% CI: 1.56-20.0), age below 60 (p=0.012, RR 8.7, 95% CI: 2.44-37.8), and absence of prosthetic ring (p=0.034, RR 4.76, 95% CI: 1.79-33.3) were all independent risk factors for reoperation. Conclusions: Mitral valve repair provides excellent survival. However, long-term outcome can be negatively influenced by perioperative risk factors. Risk of reoperation is higher in younger patients with a residual mitral regurgitation and without ring annuloplast

Decreased Excitability as a Protective Mechanism Against Repolarization Alternans-Induced Atrial Reentry

Introduction: We recently observed in human left atrium periods of intermittent 2:1 and 1:1 atrial capture, preceded by atrial repolarization alternans (Re-ALT) during rapid pacing. It remains undetermined whether Re- ALT plays a role in preventing 1:1 atrial capture over long periods of rapid pacing. Methods: We specifically developed a chronic ovine model of rapid atrial pacing using two pacemakers (PM) each with a single right atrial (RA) lead separated by ~2 cm. The 1st PM was used to record a broadband unipolar RA EGM and the 2nd one to deliver rapid pacing protocols (400 beats) at incremental rates. Activation time (AT), activation recovery interval (ARI) and beat-to-beat differences in atrial T-wave apex amplitude (ΔTa) were analyzed until the 1st beat of 2:1 capture. Results: Intermittent 2:1 capture (panel A of figure) was observed in all sheep (n=9) at a mean pacing CL of 156±26 ms. 167 episodes of intermittent 2:1 capture were analyzed. Importantly, atrial Re-ALT (panel B of figure) was observed before 2:1 capture in 73% and AT prolongation in 55% of the sequences. Only 10% of sequences showed an absence of Re-ALT and AT prolongation. Conclusions: Using an ovine model of rapid atrial pacing, our findings suggest that Re-ALT may be a mechanism causing transition from rapid 1:1 atrial capture to 2:1 capture. Because rapid atrial tachycardia slows propagation velocity and promotes fibrillatory conduction, transitions to 2:1 capture may reduce susceptibility to atrial fibrillation