Mersa M. Baryalei

Comparison of cardiac output assessed by pulse-contour analysis and thermodilution in patients undergoing minimally invasive direct coronary artery bypass grafting

OBJECTIVE To investigate the precision and accuracy of continuous pulse contour cardiac output (PCCO) compared with intermittent transcardiopulmonary (TCPCO) and pulmonary artery thermodilution (TDCO) measurements in patients undergoing minimally invasive coronary bypass surgery (MIDCAB). DESIGN Prospective, controlled, clinical study. SETTING University hospital. PARTICIPANTS Twelve patients undergoing MIDCAB. INTERVENTIONS Thirty-six measurements of PCCO and thermodilution cardiac output (CO) were simultaneously performed after the start of surgery, during bypass grafting, and at the end of surgery. TCPCO and TDCO were simultaneously assessed by three injections of ice-cold saline randomly spread over the respiratory cycle. The pulse contour device was initially calibrated with an additional set of aortic thermodilution measurements. MEASUREMENTS AND MAIN RESULTS Absolute values of CO ranged between 1.6 and 9.2 L/min. A close agreement among the three techniques was observed at all measurements. Mean bias between PCCO and TDCO and TCPCO was 0.003 L/min (2 SD of differences between methods = 1.26 L/min) and 0.27 L/min (2 SD of differences between methods = 1.16 L/min), respectively. The correlation coefficients were r2 = 0.90 for TCPCO versus PCCO and r2 = 0.88 for TDCO versus PCCO. CONCLUSION The results of the present study show that compared with thermodilution CO, pulse contour analysis enables accurate measurement of continuous CO in patients undergoing MIDCAB.

The Toronto SPV bioprosthesis: One-year results in 100 patients

BACKGROUND We studied the long-term results of heart valve replacement with the Toronto SPV bioprosthesis. METHODS From March 1993 until July 1994 the Toronto stentless bioprosthesis was implanted in 100 selected patients with a mean age of 70.7 years. The predominant aortic valve lesion was stenosis in 94 and insufficiency in 6 cases. Eighty-eight patients received a valve 25 mm in diameter or larger. Additional coronary artery bypass grafting was performed in 37 cases. Hospital mortality was 4%. Seventy-four patients were seen at 6 months and 38 patients at 1 year follow-up. RESULTS Structural deterioration, thromboembolism or hemorrhage were not encountered. Nonstructural dysfunction lead to reoperation in 1 patient. Another patient presented with endocarditis at 1 year postoperatively. There were no other valve-related complications. Echocardiographic mean pressure gradients ranged from 7.7 to 11.1 mm Hg postoperatively. There was a significant decrease in pressure gradients at 6 months of follow-up. Minimal aortic valve incompetence was seen in 3 patients. CONCLUSIONS The Toronto stentless bioprosthesis has superior hemodynamics and is an excellent alternative to conventional stented bioprostheses. Long-term evaluation has to prove whether this promising new valve can live up to its expectations.

Early results of coronary artery bypass grafting with coronary endarterectomy for severe coronary artery disease.

BackgroundDespite the existence of controversial debates on the efficiency of coronary endarterectomy (CE), it is still used as an adjunct to coronary artery bypass grafting (CABG). This is particularly true in patients with endstage coronary artery disease. Given the improvements in cardiac surgery and postoperative care, as well as the rising number of elderly patient with numerous co-morbidities, re-evaluating the pros and cons of this technique is needed.MethodsPatient demographic information, operative details and outcome data of 104 patients with diffuse calcified coronary artery disease were retrospectively analyzed with respect to functional capacity (NYHA), angina pectoris (CCS) and mortality. Actuarial survival was reported using a Kaplan-Meyer analysis.ResultsBetween August 2001 and March 2005, 104 patients underwent coronary artery bypass grafting (CABG) with adjunctive coronary endarterectomy (CE) in the Department of Thoracic-, Cardiac- and Vascular Surgery, University of Goettingen. Four patients were lost during follow-up. Data were gained from 88 male and 12 female patients; mean age was 65.5 ± 9 years. A total of 396 vessels were bypassed (4 ± 0.9 vessels per patient). In 98% left internal thoracic artery (LITA) was used as arterial bypass graft and a total of 114 vessels were endarterectomized. CE was performed on right coronary artery (RCA) (n = 55), on left anterior descending artery (LAD) (n = 52) and circumflex artery (RCX) (n = 7). Ninety-five patients suffered from 3-vessel-disease, 3 from 2-vessel- and 2 from 1-vessel-disease. Closed technique was used in 18%, open technique in 79% and in 3% a combination of both. The most frequent endarterectomized localization was right coronary artery (RCA = 55%). Despite the severity of endstage atherosclerosis, hospital mortality was only 5% (n = 5). During follow-up (24.5 ± 13.4 months), which is 96% complete (4 patients were lost caused by unknown address) 8 patients died (cardiac failure: 3; stroke: 1; cancer: 1; unknown reasons: 3). NYHA-classification significantly improved after CABG with CE from 2.2 ± 0.9 preoperative to 1.7 ± 0.9 postoperative. CCS also changed from 2.4 ± 1.0 to 1.5 ± 0.8ConclusionEarly results of coronary endarterectomy are acceptable with respect to mortality, NYHA & CCS. This technique offers a valuable surgical option for patients with endstage coronary artery disease in whom complete revascularization otherwise can not be obtained. Careful patient selection will be necessary to assure the long-term benefit of this procedure.

Renal function and safety of heart transplant recipients switched to mycophenolate mofetil and low-dose cyclosporine

BACKGROUND We evaluated cyclosporine (CSA) dose reduction and mycophenolate mofetil (MMF) treatment versus maintained CSA dosage and azathioprine (AZA) in HTX regarding renal function and safety from CSA nephrotoxicity (creatinine > 1.7 mg/dL). METHODS Fourteen recipients (group 1: 12 men, 2 women) with CSA-based immunosuppression (plus azathioprine and/or steroids) were started on 2000 mg MMF/d. Azathioprine was discontinued and CSA tapered to trough whole blood levels of 70 to 120 microg/L. Ten recipients (group 2: seven men, three women) were maintained on their CSA dosages. Creatinine clearance, serum creatinine, uric acid, urea nitrogen, and rejection were monitored. RESULTS Mean age was 58 (range 44 to 69 years) and 48 years (range 24 to 61 years) in groups 1 and 2, respectively. In group 1 creatinine fell from 2.7 +/- 0.8 to 1.9 +/- 0.5 mg/dL (baseline vs control 2: P =.001); uric acid and urea nitrogen remained constant. CSA levels decreased from 173 +/- 56 to 110 +/- 33 microg/L (P =.02). In group 2 creatinine (2.4 +/- 0.7 vs 2.3 +/- 0.5 mg/dL), uric acid, urea nitrogen, and CSA levels remained constant. Comparison between groups showed higher creatinine clearance (50 +/- 18 vs 29 +/- 14 mL/min; group 1 vs group 2: P =.02), lower CSA levels (110 +/- 33 vs 161 +/- 35 microg/L; P <.001) and a trend toward lower serum creatinine (1.9 +/- 0.5 vs 2.3 +/- 0.5 mg/dL, P =.077). There were two rejections >/= 1B according to ISHLT in the study and four in the control group. Two deaths occurred in each group. CONCLUSIONS Conversion from AZA to MMF after CSA reduction improves creatinine clearance in HTX recipients and reduces serum creatinine. No negative effect on patient safety was identified by rejection rate or survival.

Acute aortic dissection type A discloses Corpus alienum

We report an unusual case of an aortic type A dissection with a corpus alienum which compresses the right ventricle. The patient successfully underwent an aortic root replacement in deep hypothermia with re-implantation of the coronary arteries using a modified Bentall procedure and the resection of the corpus alienum. Intraoperative finding reveals 3 greatly adhered gauze compresses, which were most likely forgotten in the operation 34 years ago.

Haemodynamic changes during minimally invasive coronary artery bypass surgery using high-dose esmolol.

UNLABELLED We aimed to investigate the effects of high-dose esmolol on haemodynamics and oxygen extraction in minimally invasive direct coronary artery bypass (MIDCAB) surgery patients. METHODS In 18 patients, heart rate (HR), mean arterial (MAP), central venous (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and mixed venous oxygen saturation (Sv0(2)) were prospectively measured after induction of anaesthesia (T1), start of surgery (T2), during bypass grafting with beta-blockade (T3), and at the end of surgery (T4). RESULTS Mean esmolol dose at T3 was 0.44+/-0.2mgkg(-1)min(-1). HR was unchanged, whereas significant decreases in mean CO (3.1+/-0. 8 vs 4.8+/-1.0lmin(-1)m(-2), pre-esmolol), MAP (53+/-10 vs 89+/-14mmHg), and SvO(2) (65+/-10 vs 81+/-4%) were observed during esmolol administration. All haemodynamic parameters normalized immediately after termination of esmolol (T4). CONCLUSIONS Despite unchanged HR esmolol reduced CO and MAP suggesting a favorable reduction of myocardial oxygen consumption. Mean Sv0(2) during esmolol administration reflects an acceptable ratio of whole-body oxygen delivery and consumption. Haemodynamic changes with high-dose esmolol during MIDCAB surgery remain within safety margins.

The Stentless Toronto SPV Bioprosthesis for Aortic Valve Replacement

The Toronto SPV bioprosthesis for aortic valve replacement has been prospectively evaluated in 100 patients, since March 1993. Intraoperative transoesophageal and postoperative transthoracic echocardiography were used to assess valve function. Follow-up was complete in 74 patients at 6 months and in 38 patients at 1 year. The average valve size implanted was 26.5 mm. Some 37 patients had additional coronary artery bypass grafting surgery. The hospital mortality rate was 4%. Non-structural valve dysfunction occurred in one patient and late endocarditis in another patient required operation. There were no other valve complications. None of the patients developed clinically relevant aortic valve incompetence during follow-up and there was a significant decrease in pressure gradients, increase in valve orifice areas and decrease in left ventricular hypertrophy.

Off-Pump Supraarterial Decompression Myotomy for Myocardial Bridging

BACKGROUND Myocardial bridging of the left anterior descending (LAD) artery may result in clinical symptoms. Surgery with cardiopulmonary bypass (CPB) is a therapeutic option with considerable risk. We hypothesized that off-pump supraarterial myotomy could be an effective treatment modality. METHODS Between October 1998 and May 2000, 13 patients were referred for surgery. All were symptomatic despite medical therapy. Anteroseptal ischemia had been proven by thallium scintigraphy in all 13 patients, exercise testing was positive in 11. All patients were operated on with an off-pump approach after median sternotomy. RESULTS Mean patient age was 61 +/- 8 years (range, 43-71 years). Coronary artery disease mandating additional bypasses was present in 3 patients. The bypasses were done off pump in 2 patients. Conversion to on-pump surgery was necessary in 3 of 13 patients (23%) because of hemodynamic compromise (1 patient), opening of the right ventricle (1 patient), and injury to the LAD (1 patient). Supraarterial myotomy was performed in all patients. One patient who underwent surgery with CPB developed postoperative anteroseptal myocardial infarction. Postoperative exercise testing was performed in all patients and did not reveal any persistent ischemia. Mortality was 0%. All patients were free from symptoms and had not undergone repeat interventions after an average of 51 +/- 7 months of follow-up. CONCLUSIONS Off-pump supraarterial myotomy effectively relieves coronary obstruction but has a certain periprocedural risk as evidenced by 1 myocardial infarction, 1 right ventricular injury, and 1 LAD injury. Long-term freedom from symptoms and from reintervention favor further investigation of this surgical therapy.

Early experiences with the Medtronic FreestyleTM stentless bioprosthesis

ZusammenfassungProblemstellung: Die gerüstlose Aortenklappen-Bioprothese vom Typ Freestyle soll den gerüsttragenden Bioprothesen hämodynamisch überlegen sein. Dies veranlaßte uns zu einer prospektiven Studie mit diesem Klappentyp.¶Material und Methode: Zwischen Mai 1996 und Juni 1997 wurde bei 58 Patienten ein Aortenklappenersatz (AKE) mit der Freestyle Bioprothese durchgeführt. Das Durchschnittsalter lag bei 73,8 Jahren (range 60–84), 45 Patienten waren über 70 Jahre alt. 29 Patienten hatten eine Aortenklappenstenose, 10 eine Aorteninsuffizienz. Um ein kombiniertes Vitium handelte es sich bei 19 Patienten. 83% der Patienten waren praeoperativ in einem Stadium NYHA III oder IV. Alle Patienten wurden klinisch und mittels transthorakaler Echokardiographie 1 Woche, 6 Monate und 1 Jahr postoperativ nachuntersucht.¶Ergebnisse: 26 Patienten erhielten aufgrund einer symptomatischen KHK zusätzlich Bypasses. Die mittlere Ischämiezeit betrug 55min (range 41–95) bei isoliertem AKE und 71min (52–103) bei zusätzlicher Anlage von Koronarbypasses. Die perioperative Letalität lag bei 7% (4/58). Nach 12 Monaten waren 41% (24) der untersuchten Patienten im Stadium NYHA I und 53% (31) in NYHA II.¶Schlußfolgerungen: Der Einsatz der Freestyle Bioprothese führt zu einer deutlichen klinischen Verbesserung der Patienten, die postoperativ nahezu alle in NYHA I oder II sind. Die perioperative Mortalität ist niedrig, so daß die Verwendung dieser Klappe sicher ist. Längeres Follow-up muß bestätigen, daß die günstigen Frühergebnisse persistieren und mit einer längeren Haltbarkeit der Klappe einhergehen als es bei konventionellen gerüsttragenden Bioprothesen der Fall ist.SummaryBackground: Stentless porcine aortic valves are considered to be hemodynamically superior to mounted bioprostheses.¶Methods: From May 1996 to June 1997, 58 consecutive patients underwent aortic valve replacement with the Freestyle stentless bioprosthesis in the subcoronary position. Mean age was 73,8 years (range 61–84). The predominant aortic valve lesion was stenosis in 29 and regurgitation in 10 cases. A combined lesion was found in 19 patients. All patients were examined clinically and by echocardiography 1 week, 6 months, and 1 year postoperatively.¶Results: Additional coronary artery bypass grafting was performed in 26 patients. Mean cross-clamp time was 55 min (range 41–95) for AVR and 71 min (range 52–103) with additional CABG. The inhospital mortality rate was 7% (4/58). Thromboembolism, hemorrhage, endocarditis or structural valve deterioration did not occur. At one year 41% were in NYHA class I, 53% in NYHA class II. Minimal aortic valve incompetence was seen in 19% postoperatively, in 14% at 6 months and in 9% at 1 year. There was no case of severe regurgitation.¶Conclusions:The Freestyle stentless bioprosthesis shows good results both hemodynamicaly and clinically. Pressure gradients are decreasing and most of the Patients are in NYHA functional class I or II postoperatively. Perioperative mortality is low and no valve related complications occured suggesting this type of valve to be safe. Whether this promising valve can live up its expectations has yet to be determined in long-term follow-up studies.