Constantin Stefanidis

Continuous mixed venous and central venous oxygen saturation in cardiac surgery with cardiopulmonary bypass.

Background and objective Replacing mixed venous oxygen saturation (SvO2) monitoring by central venous oxygen saturation (ScvO2) monitoring in order to avoid the use of a pulmonary artery catheter and its related complications is still controversial in the setting of cardiac surgery. The influence of surgery, cardiopulmonary bypass and anaesthesia drugs on the relationship between SvO2 and ScvO2 has never been studied. Methods Fifteen patients scheduled for cardiac surgery with cardiopulmonary bypass were included in the study. SvO2 (from the pulmonary artery) and ScvO2 (from the superior vena cava) were continuously measured with fibre-optic catheters from induction of anaesthesia to 24 h postoperatively. Results A total of 9267 pairs of measurements were recorded. Mean bias between SvO2 and ScvO2 was 4.4% with limits of agreement of −13.6 and +22.5%, respectively. Trends of SvO2 and ScvO2 values followed very different patterns for some patients. Surgery, cardiopulmonary bypass and anaesthesia drugs did not influence the relationship between the two methods. Conclusion Because of the large interindividual variability in the difference between SvO2 and ScvO2, the measure of ScvO2 should not replace the measure of SvO2 with a pulmonary artery catheter for the management of patients undergoing cardiac surgery with cardiopulmonary bypass.

Oxidative stress produced by circulating microparticles in on-pump but not in off-pump coronary surgery.

Objective — This study was undertaken to assess whether plasmas isolated during off-pump coronary surgery trigger less oxidative stress than those isolated during on-pump surgery. Methods and results — Plasmas were sampled from patients before (T0), just after (T1) and 24 hours after (T2) cardiac surgery (n = 24 on-pump and n = 10 off-pump). Rings of rat thoracic aortas were incubated for 20 hours with these different plasmas (100 μl + 4 ml medium) or saline (control). Thereafter, superoxide anion production was assessed by chemiluminescence and the mean signal was expressed as percent of that in the control ring. In rat aorta exposed to plasmas from on-pump CABG patients (n = 6), the signal was enhanced by 210 ± 29% at T1 (P < 0.05) and by 174 ± 29% at T2 (P < 0.05) versus 53 ± 12% at T0. Moreover, at T1 and T2, there was an upregulation of p22phox , the key subunit of NADPH oxidase, the main enzyme involved in oxidative stress of the vascular wall. In contrast, off-pump plasmas did not induce this superoxide production. Incubation with microparticles obtained by ultracentrifugation also markedly enhanced the signal at T1 and T2 (vs. T0) in the on-pump group (but not in the off-pump group). Selective removal of CD34, CD105, CD59, CD146, CD42 microparticles using flow cytometry did not abolish the signal. CRP and SAA plasma levels were enhanced only at T2 in both groups. Conclusions — Plasmas isolated after on-pump but not off-pump coronary bypass surgery can induce superoxide generation by the vascular wall which seems related to circulating microparticles remaining present at least 24 hours after the procedure that might be of endothelial origin.

Pulmonary vein isolation by robotic-enhanced thoracoscopy for symptomatic paroxysmal atrial fibrillation.

BACKGROUND Pulmonary vein isolation (PVI) has been shown to be effective treatment of patients with symptomatic paroxysmal atrial fibrillation (PAF). The percutaneous approach is currently the technique of choice. Unfortunately, this procedure has limitations and complications that lead to fluctuating success rates. We explored an alternative technique of robotic-enhanced, closed-chest PVI with an endoscopic microwave-based catheter. METHODS Seven symptomatic PAF patients were included in the study. The pulmonary veins were isolated through right (only) robotic-enhanced thoracoscopy on the beating heart. RESULTS Six patients underwent successful endoscopic PVI. In 1 patient the operation was converted into small right thoracotomy. Operative assessment of the ablation line showed a successful electric block in every patient. Three months after the procedure, the first 5 patients were in permanent sinus rhythm. The 2 other patients had AF but had less frequent and less symptomatic episodes compared with the preoperative situation. CONCLUSIONS On the basis of this preliminary experience, we believe that in the near future endoscopic right-chest robotic-enhanced PVI on the beating heart may become a valid option in the treatment of symptomatic PAF patients. This procedure allows for more-reproducible ablation lines and may avoid many of the pitfalls and drawbacks of the percutaneous approach. Therefore this technique deserves larger prospective evaluation in the treatment of AF.

Esophageal perforation by echoprobe during cardiac surgery: treatment by endoscopic stenting

The usefulness and safety of transesophageal echocardiography during cardiac surgery have been well described in the literature. However, rare complications of this procedure can occur and should be familiar to surgeons and anesthesiologists. A case of esophageal perforation by echoprobe during coronary artery bypass grafting treated successfully by endoscopic stenting is reported.

Acute aortic dissection after off-pump coronary artery surgery.

Iatrogenic aortic dissection has been described, albeit infrequently, after coronary artery surgery performed under cardiopulmonary bypass. Since the advent of beating heart coronary surgery, several authors have described an apparent increase of this complication related to the application of a lateral clamp on the ascending aorta to perform the proximal anastomosis. We describe the case of a 70 years old patient who presented aortic dissection, with immediate paraplegia, 7 days after off-pump coronary surgery.

Popliteal artery pseudo-aneurysm and hereditary multiple exostoses.

Abstract We describe a rare case of a 21-year-old man presenting with hereditary multiple exostosis and a pseudo-aneurysm of the popliteal artery caused by femoral osteochondroma. Principles of management and surgical technique are discussed.

Endocarditis of bovine jugular vein conduit due to Q fever.

Contegra (Medtronic, Minneapolis, MN) conduits are routinely used in cases of right ventricular outflow tract reconstruction during congenital heart surgery. We report two cases of Q fever endocarditis involving Contegra conduits. Surgical treatment and distinct aspects of both unusual cases are described.

FIVE YEARS FOLLOW-UP AFTER Y-GRAFT ARTERIAL REVASCULARIZATION: ON PUMP VERSUS OFF PUMP; PROSPECTIVE CLINICAL TRIAL

OBJECTIVES We report our comparative experience of on-pump and off-pump full arterial coronary artery bypass grafting (CABG) using both internal mammary arteries (IMAs) anastomosed as a Y-graft. METHODS A single-center clinical study was conducted prospectively between January 2003 and May 2008. It compared the short- and mid-term clinical outcomes of on- and off-pump arterial revascularization where the left internal mammary artery (LIMA) was anastomosed to the left anterior descending (LAD) artery while the free right internal mammary artery (RIMA) graft taking off from the LIMA was used to bypass different coronary targets. RESULTS One hundred and ninety-two patients were divided into 77 on-pump and 115 off-pump procedures based on the intention to treat. The mean age in both groups was 60.2+/-11.7 and 68.1+/-10.6 years, respectively (P<0.05). Mean predictive logistic EuroSCORE was 3.5+/-6.7% for the on-pump group and 7.3+/-8.6% for the off-pump group (P<0.0001). Mean number of distal anastomoses were 2.7+/-0.6 (group ON) and 2.5+/-0.6 (group OFF) (P=NS). Postoperative mortality was two patients (2.6%) in the on-pump group and four patients (3.4%) in the off-pump group (P=0.63). No major adverse cardiac event, no stroke and no late death were reported during the follow-up that averaged 36.5+/-18.6 months. Angina recurrence was three patients (2.6%) in off-pump and two patients (3.5%) in on-pump group (P=NS). CONCLUSIONS The use of a free RIMA as Y-graft from the LIMA performed off pump eradicates aortic manipulations and provides complete revascularization to high-risk patients with mortality similar to the one of a lower risk population operated on pump. The morbidity and cost was lower in the off-pump group. This advocates for the widespread usage of the technique in high-risk patients.

Gonococcal ascending aortic aneurysm with penetrating ulcer and bovine arch.

We describe a patient with ascending aorta aneurysm and bovine aortic arch who initially presented with fever. A 65-year-old man with a 2-month history of intermittent fever was referred to our hospital and diagnosed as having a gonococcal ascending aorta aneurysm with penetrating ulcers. He was successfully treated by resection of the ascending aorta and ulcers, replacement of the aortic valve, and prolonged postoperative antibiotic therapy.