Prolonged Cross-clamp Time Research Articles

Endovascular approach to complex aortic arch pathologies: state of the art.

Aortic geometry changes during life [1]. After relatively dynamic aortic length and diameter growth in the first two decades of life, it continuous to grow, attaining diameters 20 to 30% larger in the 7th than in the 2nd decade. Arterial hypertension, atherosclerosis, and still poorly-defined genetic risk factors add to natural aortic anatomy changes leading to rapid aortic segmental growth and ultimately aneurysms. Aortic arch aneurysms together with arch dissections and penetrating atherosclerotic ulcers are the most common arch pathologies requiring further therapy. New technologies give us an excellent opportunity to broaden the surgical armamentarium. Thoracic endovascular aortic repair (TEVAR) has dramatically changed aortic surgery within the last 15 years. It is not only a far less invasive approach than open surgery, but it also provides excellent results for complex pathologies in certain patients and may be applied even in those ineligible for open surgery [2, 3]. Thoracic endovascular aortic repair became the treatment of choice for traumatic aortic injury and acute complicated type B dissection. Aortic arch pathologies due to the arch's key role in maintaining cerebral perfusion usually require complex treatment. Several hybrid surgical techniques have been developed in the last decade, which combine an endovascular and open approach to obtain better results. The hybrid approach includes hybrid surgical procedures (TEVAR combined with surgical rerouting of supraaortic vessels) and the hybrid devices originating from traditional prostheses employed during open and endovascular procedures. The hybrid approach to the aortic arch is associated with less trauma, usually no need for the heart-lung-machine, no need for hypothermia or artificial cerebral perfusion, and no risk or recurrent nerve paresis. The complications related to hybrid procedures include retrograde aortic dissection type A, endoleaks, and stentgraft migration. According to the Penn classification, there are three types of hybrid approach to aortic arch pathologies [4]. Type I includes supraaortic vessels debranching using a 4 limb branched graft anastomosed to the very proximal ascending aorta (just above the sinotubular junction) and on the other side to all supraaortic vessels. The fourth branch is used to insert the stent graft in antegrade direction into the aortic arch. Type I is being performed only sporadically since it carries a relatively large risk of retrograde aortic dissection type A. Type I hybrid approach is contraindicated in case the ascending aorta diameter exceeds 3.8 cm. More popular is type II hybrid approach consisting of creating a zone 0 landing zone by replacing the ascending aorta in an open fashion and debranching the supraaortic vessels similar to type I, followed by the TEVAR procedure [5]. Its main advantage is that it is not associated with the risk of retrograde dissection. However, it necessitates sternotomy and the heart-lung-machine. Penn type III hybrid approach is a frozen-elephant-trunk procedure that includes total aortic arch replacement and stentgraft implantation in the proximal descending thoracic aorta using a hybrid prosthesis. Total endovascular arch replacement is now feasible, and two similar devices are already available. Both include one main stent graft specifically for implantation starting in the ascending and ending in the proximal thoracic descending aorta (Fig. 1). Both have 2 internal tunnels (inner branches) that are extended with stent grafts into the brachiocephalic trunk and the carotid artery. This operation requires prior carotid-subclavian bypass on the left side [6]. The ascending aorta diameter should not exceed 3.8 cm. Fig. 1 Double inner branched stent graft in the aortic arch of the patient with penetrating atherosclerotic ulcer. A – aortic stent graft, B – brachiocephalic trunk, C – left carotid artery, D – carotid-subclavian bypass The open-surgical approach to the aortic arch is the gold standard. Further development of less invasive endovascular treatment options is mandatory, since they may be beneficial for older patients with significant comorbidities who may not tolerate prolonged cross-clamp and circulatory arrest times. Transcatheter aortic valve implantation technology has not reduced the number of conventional aortic valve replacement procedures. Similarly, although endovascular aortic arch replacement is not likely to replace open surgery, it will expand our armamentarium and enable us to recruit new patients undergoing medical treatment only due to their excessive risk of conventional arch replacement.

Survival, Neurologic Injury, and Kidney Function after Surgery for Acute Type A Aortic Dissection.

To analyze survival, neurologic injury, and kidney function after acute type A aortic dissection. A total of 445 patients undergoing surgery for acute type A aortic dissection were analyzed. Evaluation according to risk factors for mortality, neurologic injury, and kidney function was performed. Overall 1-, 5-, and 10-year survival rates were 82.8 ± 1.8%, 73.6 ± 2.4%, and 59.3 ± 3.9, respectively. Independent preoperative risk factors for mortality were preexisting renal impairment (p = 0.001), reduced left ventricular ejection fraction (p < 0.001), and age (p < 0.001). Perioperative risk factors were prolonged cross-clamp (p < 0.001) and cerebral perfusion time (p = 0.001). Risk factors for renal failure were preexisting renal impairment (p < 0.001), prolonged cross-clamp time (p < 0.001), cerebral perfusion time (p < 0.001), and age (p = 0.022). Risk factors for neurologic injury were cross-clamp time (p = 0.038), cerebral perfusion time (p = 0.007), and age (p = 0.045). In addition to classic risk factors, survival after type A aortic dissection is affected by preexisting renal impairment. Preexisting renal impairment is predictive of postoperative renal failure. Therefore treatment and prevention strategies for renal failure during the acute and long-term course after acute type A aortic dissection are warranted.

Independent Risk Factors for Fast-Track Failure Using a Predefined Fast-Track Protocol in Preselected Cardiac Surgery Patients.

The purpose of this study was to identify the independent risk factors for fast-track failure (FTF) in cardiac surgery patients. A retrospective analysis. A university-affiliated heart center. In a 2-year period, 1,704 consecutive preselected patients undergoing elective cardiac surgery were treated according to the local fast-track protocol in the postanesthetic care unit (PACU), bypassing the intensive care unit (ICU). Independent risk factors for FTF in the univariate regression analysis were tested in a multivariate regression analysis. FTF was defined as any transfer of the preselected patient to the ICU. FTF was primary when the patient was transferred directly from the postanesthetic care unit to the ICU and secondary when the patient was transferred from the intermediate care unit or ward to the ICU. FTF rate was 11.6% for primary and 5.6% for secondary FTF. In the multivariate regression analysis, age>70 years, female sex, prolonged surgery, and prolonged cross-clamp time could be defined as independent risk factors for FTF. In a preselected patient population, fast-track treatment could be done with a low FTF rate. Independent risk factors for FTF are age, female sex, prolonged surgery, and prolonged cross-clamp time.

Is it possible to predict the risk of ischaemic bowel after cardiac surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is it possible to predict the risk of ischaemic bowel after cardiac surgery?' Altogether 80 papers were found as a result of the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence topic presents 68 214 cardiac surgical patients from seven major cardiothoracic centres dated from 1980 to 2011. The incidence and mortality rates of bowel ischaemia after cardiac surgery range from 0.07-0.5 and 59-64%, respectively. Advanced age and peripheral vascular disease are the common preoperative risk factors, which were reported by 3 papers each. The most common intraoperative risk factors were prolonged cross-clamp and cardiopulmonary bypass time, which were reported by 3 papers each. Five of 7 papers reported that the use of intra-aortic balloon pump was a significant risk factor. The use of inotropes, postoperative blood loss and postoperative renal failure were reported by 3 of 7 papers, each to be a significant risk factor for postoperative bowel ischaemia in cardiac surgery patients. We, therefore, conclude that these are probably the most significant and useful predictive risk factors for bowel ischaemia after cardiac surgery. Thus, careful intraoperative management to minimize cardiopulmonary bypass and cross-clamp time and optimal care of patients' postoperative haemodynamic status, particularly in elderly patients with severe atherosclerotic disease, are useful in preventing this rare but lethal postoperative complication. Besides that, a heightened clinical suspicion in patients with these risk factors may lead to prompt diagnosis of bowel ischaemia, allowing intervention to prevent mortality. The variability of the study design and risk factors studied in each paper impose limitation to summarize the predicting risk factors.

Conversion rate and contraindications for minimally invasive mitral valve surgery.

Over the past 15 years, minimally invasive mitral valve surgery via right lateral minithoracotomy has become the preferred method for mitral valve repair and mitral valve replacement in specialized centers worldwide. This technique refers to specific operation and visualization technologies and new perfusion methods. The minimally invasive approach affords faster patient recovery, less pain, shorter hospital stay and improved cosmesis. Moreover, minimally invasive mitral valve surgery may be an alternative to conventional mitral valve surgery, given that there is comparable short- and long-term mortality and comparable in-hospital morbidity. However, several studies have shown an increased risk of stroke, aortic dissection, groin infections, prolonged cross-clamp time and cardiopulmonary bypass time (1). Owing to severe intraoperative difficulties, conversion to full sternotomy is also a serious complication. At our institution, we have a very extensive experience with minimally-invasive mitral valve surgery, dating back to the late 1990s (2). We therefore aim to review the reasons and the early postoperative outcomes for those patients who underwent conversion to full sternotomy. Furthermore, we outline the contraindications for minimally-invasive mitral valve surgery.

The Anesthetic Management of a Patient with Marfan Syndrome and Renal Transplant Patient Undergoing Bentall Operation

The Anesthetic Management of a Patient with Marfan Syndrome and Renal Transplant Patient Undergoing Bentall OperationMarfan syndrome (MFS) is a genetic disorder with a high mortality rate which causes aortic aneurysm and aortic insufficiency. Bentall procedure is an aortic root and valve surgery which can maintain near-normal life time in MFS patients, however prolonged extracorporeal circulation and cross-clamp times is the drawback of the procedure. In this case report, we discussed the anesthesia management of a patient with MFS and history of renal transplantation undergoing Bentall procedure.

Risk factors of prolonged mechanical ventilation following open heart surgery: what has changed over the last decade?

To identify the risk factors for prolonged invasive mechanical ventilation after open heart surgery in Pakistan. This study is based on retrospective analysis of database. We conducted study of all patients who underwent open heart surgery at CPE Institute of Cardiology, Multan from March 2009 to May 2011. The data was retrieved from the database in the form of electronic spreadsheet which was then analyzed using SPSS software. The patients with incomplete data entries were removed from the analysis resulting in a set of 1,617 patients. The data of each patient consisted of 65 preoperative, operative and postoperative variables. The data was summarized as means, medians and standard deviations for numeric variables and frequencies and percentages or categoric variables. These risk factors were compared using Chi-sqaure test. Their ODDs ratios and 95% confidence intervals of ODD's Ratios and P values were calculated. Out of a total of 1,617 patients, 77 patients (4.76%) had prolonged ventilation for a cumulated duration of more than over 24 hours. Preoperative renal failure, emphysema, low EF (<30%), urgent operation, preoperative critical state, prolonged bypass time, prolonged cross clamp time, complex surgical procedures and peri-operative myocardial infarction were found to be risk factors for PIMV. Old age, female gender, advanced ASA class, advanced NYHA class, diabetes mellitus, smoking, history of COPD, redo surgery, left main stenosis, obesity and use of intra-aortic balloon pump were not found to have significant ODDs ratios for PIMV. The patients with prolonged ventilation had significantly high mortality i.e. 32.47% while the normal ventilation group had 0.32% overall mortality. Many of the previously considered risk factors for prolonged ventilation after open heart study are no more significant risk factors. However, prolonged ventilation continues to be associated with very high mortality.

ST-elevation myocardial infarction with preserved ejection fraction: The impact of worsening renal failure

normal aortic root morphology may benefit the most from aortic valve replacement with a Perceval, without increased risk of death or other major complications. In our patient, the complex combined surgical procedure was characterized by prolonged cross-clamp and CPB times. The use of conventional bioprosthetic valves, however, would have resulted in a significantly longer implantation time. In case of combined surgery, completion of proximal graft anastomoses before CPB using tangential clamping may further reduce the ischemic time, avoiding aorta manipulation after valve deployment. Although this technique cannot be recommended as an alternative to TAVI in patients undergoing surgical myocardial revascularization, this approach may be considered in patients with a heavily calcified ascending aorta to reduce the ischemic time during aortic valve surgery with potential beneficial effects on postoperative outcome. Sutureless aortic valves may therefore represent a useful tool in the armamentarium of cardiac surgeons for combined surgery, allowing to achieve a dramatic reduction in implantation times of prosthetic aortic valves.

Reply to Santarpino et al.

We thank Dr Santarpino et al. for their comments in connection with our recently published work [1, 2]. Essentially, they raise the much valid point of a potential reduction in procedural invasiveness in high-risk profile conventional aortic valve replacement (AVR). Adequate surgical exposure with reduction in operative trauma remains the mainstay of development of minimally invasive AVR approaches. A growing body of literature addresses this at three levels: limited incisions, cardiopulmonary bypass circuit modifications and recently sutureless prostheses. We have experience with both mini-incisions and miniaturized circuits specifically for AVR in that respect [3, 4]. Although it is our belief that prolonged cross-clamp time is a surrogate marker of case complexity and intraoperative technical difficulties encountered, we agree that any attempt to reduce this would be beneficial. Interestingly, Nissinen et al. associated cross-clamp time <150 min with a low risk of immediate postoperative adverse events [5]. Developments in the field of transcatheter valve technologies have reinstigated an interest in sutureless valves. Unequivocally an appealing option for demanding cases such as small and calcified aortic root/annulus or potentially complex cases where prolonged bypass and cross-clamp times are anticipated, pilot studies for sutureless AVR have shown encouraging results [6]. At present, we accept the trade-off between prolonged cross-clamp time and post-operative paravalvular leaks in conventional and sutureless AVR, respectively, as it remains to be shown that the associated cross-clamp time reduction translates in clinically improved outcomes regarding morbidity and mortality. Therefore, as with any new technology, its application should be confined within the boundaries of appropriately designed clinical trials prior to the change of conventional practice.

Minimally Invasive versus Open Mitral Valve Surgery a Consensus Statement of the International Society of Minimally Invasive Coronary Surgery (ISMICS) 2010

: The purpose of this consensus conference was to deliberate the evidence regarding whether minimally invasive mitral valve surgery via thoracotomy improves clinical and resource outcomes compared with conventional open mitral valve surgery via median sternotomy in adults who require surgical intervention for mitral valve disease. : Before the consensus conference, the consensus panel reviewed the best available evidence up to March 2010, whereby systematic reviews, randomized trials, and nonrandomized trials were considered in descending order of validity and importance. The accompanying meta-analysis article in this issue of the Journal provides the systematic review of the evidence. Based on this systematic review, evidence-based statements were created for prespecified clinical questions, and consensus processes were used to derive recommendations. The American Heart Association/American College of Cardiology system was used to label the level of evidence and class of each recommendation. : Considering the underlying level of evidence, and notwithstanding the limitations of the evidence base (retrospective studies with important differences in baseline patient characteristics, which may produce bias in results of the evidence syntheses), the consensus panel provided the following evidence-based statements and overall recommendation:In patients with mitral valve disease, minimally invasive surgery may be an alternative to conventional mitral valve surgery (Class IIb), given that there was comparable short-term and long-term mortality (level B), comparable in-hospital morbidity (renal, pulmonary, cardiac complications, pain perception, and readmissions) (level B), reduced sternal complications, transfusions, postoperative atrial fibrillation, duration of ventilation, and intensive care unit and hospital length of stay (level B). However, this should be considered against the increased risk of stroke (2.1% vs 1.2%) (level B), aortic dissection (0.2% vs 0%) (level B), phrenic nerve palsy (3% vs 0%) (level B), groin infections/complications (2% vs 0%) (level B), and, prolonged cross-clamp time, cardiopulmonary bypass time, and procedure time (level B). The available evidence consists almost entirely of observational studies and must not be considered definitive until future adequately controlled randomized trials further address the risk of stroke, aortic complications, phrenic nerve complications, pain, long-term survival, need for reintervention, quality of life, and cost-effectiveness.

Cross-clamp time is an independent predictor of mortality and morbidity in low- and high-risk cardiac patients

Objectives We sought to assess the effects of aortic cross-clamp time (XCL) on outcome following cardiac surgery in low- and high-risk patients. Methods This is a retrospective review of prospectively collected departmental data of all patients who underwent cardiac surgery over 8-year period. Our cohort consisted of 3799 consecutive patients subdivided into low-risk (Euro SCORE < 6, n = 2691, 71%) and high-risk (Euro SCORE ≥ 6, n = 1108, 29%). Each class was further stratified into three groups based on their corresponding XCL time. Group 1 (XCL ≤ 60 min), group 2 (XCL > 60 but ≤ 90 min) and group 3 (XCL >90 min). Postoperative morbidity and in-hospital mortality were analysed. Results Univariate analysis showed the following to be significantly associated with increased XCL time in both low- and high-risk patients: low cardiac output, prolonged ventilation time, renal complications, prolonged hospital stay, blood transfusion and increased mortality ( p < 0.05). By using multiple logistic regression, aortic XCL time >60 min was independent risk factor for low cardiac output, prolonged ventilation, renal complication, blood transfusion, mortality and prolonged hospital stay in both groups. By using XCL time as a continuous variable, an incremental increase of 1 min interval in XCL time was associated with a 2% increase in mortality in both groups. Conclusion Prolonged cross-clamp time significantly correlates with major post-operative morbidity and mortality in both low- and high-risk patients. This effect increases with increasing XCL time. Prior knowledge on this effect can help in preventing some of these complications.

Pediatric Warm Open Heart Surgery and Prolonged Cross-Clamp Time

Pediatric Warm Open Heart Surgery and Prolonged Cross-Clamp Time

Pediatric Warm Open Heart Surgery and Prolonged Cross-Clamp Time

The safety of normothermic pediatric cardiac surgery remains controversial. This study evaluated the performance of normothermic cardiopulmonary bypass (CPB) associated with intermittent warm blood cardioplegia during prolonged aortic cross-clamp time (CCT). This retrospective study included 234 consecutive patients weighing less than 10 kg operated under CPB from August 2006 to November 2007. Patients were divided into two groups: group 1 contained 38 patients with CCT exceeding 90 minutes, and group 2 had 196 patients with shorter CCT. Classic factors were used to analyze outcomes, and outcomes were compared with those from the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery database. Results, expressed as values for group 1 vs those for group 2, were mortality rate, 5.3% vs 2%; length of hospital stay exceeding 21 days, 5% vs 0.5%; delayed chest closure, 21% vs 2.6%; epinephrine infusion, 45% vs 11%; organ failure, 13% vs 2%; reoperation due to bleeding, 3% vs 0.5%; heart block, 3% vs 1%; time to extubation, in hours, 64 +/- 94 vs 19 +/- 48; plasma lactate concentrations after bypass, 2.6 vs 1.9 mmol/L; length of stay in intensive care, in hours, 100 +/- 105 vs 52 +/- 48. Despite expected differences between the two groups, our results were within the range of values described in the literature. This led us to conclude that warm pediatric cardiac surgery with a long CCT is safe. A large, multicenter, randomized prospective study comparing normothermic and hypothermic pediatric cardiac surgery is underway.

Incidence and pathophysiology of atrioventricular block following mitral valve replacement and ring annuloplasty

In this retrospective study we evaluate the causative mechanisms underlying postoperative atrioventricular block (AVB) following mitral valve replacement and mitral valve annuloplasty. Between January 1990 and December 2003, 391 patients underwent mitral valve replacement or ring annuloplasty and quadrangular resection. Exclusion criteria were preoperative AV block, two or three valvular procedures, reoperations and procedures combined with coronary artery bypass grafting. The presence of the postoperative AVB was compared with preoperative and intraoperative variables. On 55 post-mortem specimens the relationship between the AV node, AV node artery and mitral valve annulus was investigated. The mean age was 59+/-14 years and 44% of patients were female. Postoperatively AVB occurred in 92 (23.5%) patients. AVB III was found in 17 (4%) patents, in whom a pacemaker was implanted within median interval of 4 days. Second degree AVB occurred and first degree AVB in five (1.3%) and in 70 (18%) patients respectively. In dry dissected human hearts in 23% of investigated cases the AV node artery was discovered to run close to the annulus of the mitral valve. Data collected in this study showed that, sotalol and amiodarone as well as a prolonged cross-clamp time may slightly influence the 23% incidence of postoperative AVB. The morphological investigation showed that the AV node artery runs in close proximity to the annulus in 23% of cases. We speculate that damage of the AV node artery may play a role in development of AVB.

Bridging circuit for the resection of retroperitoneal sarcoma involving the aorta and the IVC - veno-venous to veno-arterial perfusion

A 50-year-old female underwent surgery for removal of a massive retroperitoneal sarcoma (RPS) involving the right hepatic lobe and the inferior vena cava (IVC), abdominal aorta, right lung, right hemi-diaphragm and pericardium. Resection of the RPS necessitated cross-clamping of the abdominal aorta, IVC and the hepatic artery. Cross-clamp time cannot be predicted prior to tumour resection and vascular re-construction. To prevent complications of prolonged cross-clamp time and distal hypo-perfusion, circulatory support was sought to facilitate the procedure. A perfusion circuit was designed to accommodate an easy and immediate redirection of blood flow from venovenous bypass (VVB) to veno-arterial bypass (VAB) without requiring a change of circuit and with minimum heparin administration. Furthermore, this circuit provides the added safety of an oxygenator and a heat-exchanger. Utilising the circuit enabled successful resection of the RPS. The patient was discharged from the intensive care unit (ICU) seven days later without any post-operative complications. This case report of a design of a perfusion circuit for the resection of RPS made use of a perfusion approach that had not previously been described and allowed for a reduction in the duration of ischaemic time and retroperitoneal bleeding.

Abdominal aortic aneurysm repair and colonic infarction: a risk factor appraisal

Colonic infarction is a recognized complication of abdominal aortic aneurysm (AAA) surgery. The clinical difficulty in establishing the diagnosis combined with the patient's poor physiological status is usually associated with a fatal outcome. We assessed our experience with this problem to identify a possible risk factor profile for these patients. Patients records were identified from the operative logs, intensive care unit, Hospital Inpatient Enquiry system and vascular unit databases over a 6-year period. A total of 405 patients underwent AAA repair during this period; 140 as emergency ruptures. Nine patients were identified from the databases with known colonic infarction (2.2%). One was a woman. The mean age was 70 years. Seven patients had emergency ruptures (5%). Twenty independent risk factors were analysed using univariate and multivariate logistic regression models. Significant risk factors identified by using a multivariate analysis included the nature of the presenting patient, preoperative hypotension, prolonged cross-clamp time, intra-operative ischaemia and postoperative acidosis. Confirmatory diagnosis was made by colonoscopy in eight patients. One patient survived following the salvage surgery. The mean duration of survival was 10.5 days. The overall mortality was 89% of patients. In our unit infrarenal AAA repair has a 2.2% rate of colonic infarction. A definitive diagnosis is best made by colonoscopy. A risk factor profile for the development of colonic infarction may be constructed on the basis of specific clinical parameters. Earlier intervention on the basis of this profile may ultimately reduce the current excessive mortality.

Effect of Pexelizumab in Coronary Artery Bypass Graft Surgery With Extended Aortic Cross-Clamp Time

Prolonged cross-clamp time during cardiac surgery increases the risk of postoperative mortality and myocardial injury. This subanalysis from the pexelizumab for reduction of infarction and mortality in coronary artery bypass grafting surgery (PRIMO-CABG) trial, a phase III double-blind, placebo-controlled study of 3,099 patients undergoing on-pump coronary artery bypass graft surgery with or without valve surgery, assessed the impact of pexelizumab, an investigational C5 complement inhibitor, on postoperative outcomes after prolonged aortic cross-clamp time. The composite endpoint of death or myocardial infarction through postoperative day 30 and death alone through days 30, 90, and 180 were examined in subpopulations of patients across different cross-clamp times. After prolonged cross-clamping (> or = 90 minutes), death, or myocardial infarction through day 30 and death through days 30, 90, and 180 were significantly increased in the intent-to-treat population and were even higher in patients with two or more prespecified risk factors, compared with all patients cross-clamped less than 90 minutes. Pexelizumab significantly reduced the incidence of death or myocardial infarction through day 30, and significantly reduced the incidence of mortality through day 180, in patients with two or more risk factors that required prolonged cross-clamp time. Pexelizumab also significantly reduced perioperative myocardial injury in all patients requiring prolonged cross-clamp time. In this retrospective, subgroup analysis, pexelizumab reduced postoperative morbidity and myocardial injury in patients with multiple risk factors who underwent prolonged cross-clamp time during coronary artery bypass surgery. The clinical benefit of pexelizumab may be related to the effect of complement inhibition in the presence of potential ischemic-reperfusion injury associated with prolonged aortic cross-clamp time.

Implantation of a Modified Freestyle Valve With a Single Inflow Suture Line: Technical Patterns and Advantages

Subcoronary implantation of stentless valves may be a surgical challenge in the small aortic root. In addition, calcifications of coronary ostia may interfere with the procedure. We present a technique to trim a Freestyle stentlesss root (Medtronic Inc, Minneapolis, MN) and facilitate implantation with a single inflow suture line.

Histological study of colonic ischaemia after aortic surgery.

Colonic ischaemia is a well documented complication of abdominal aortic reconstruction. In this prospective study patients had routine preoperative and postoperative colonoscopy and biopsy, in order to determine the true incidence and implications. Fifty-six patients undergoing elective infrarenal aortic surgery, 28 for aneurysm and 28 for occlusive disease, had colonoscopy and biopsy before and 1 week after operation. Colonic ischaemia was identified histologically in biopsies from 16 (30 per cent) of 53 patients. Almost half the patients had normal macroscopic appearances. Two factors exhibited a statistically significant association with the development of ischaemia: prolonged cross-clamp time (P < 0.05) and postoperative diarrhoea (P< 0.001). Co-morbidity was much higher in patients with colonic ischaemia (P< 0.005). Overall morbidity was significantly greater in the aneurysm group (P < 0.05). Colonic ischaemia is common after aortic reconstruction. When suspected, colonoscopy with biopsy is diagnostic.

Continuous monitoring of myocardial acid–base status during intermittent warm blood cardioplegia☆

Intermittent warm blood cardioplegia (IWBC) is a well-established technique for myocardial protection during cardiac operations. According to standardized protocols, IWBC administration is currently performed every 15-20 min regardless of any individual variable and in the absence of any instrumental monitoring. We devised a new system for continuous measurement of the acid-base status of coronary sinus blood for on-line evaluation of myocardial oxygenation during IWBC. In 19 patients undergoing cardiac surgery for coronary artery bypass graft and/or valve surgery and receiving IWBC (34-37 degrees C) by antegrade induction (3 min) and retrograde or antegrade maintenance (2 min) every 15 min, continuous monitoring of myocardial oxygenation and acid/base status was performed by means of a multiparameter PO(2), PCO(2), pH, and temperature sensor (Paratrend7 (R), Philips Medical System) inserted into the coronary sinus. Mean cross-clamping time was 76+/-26 min; ischemic time was 13+/-0.2 min. pH decline was not linear, showing an initial fast decline, a point of flexus, and a progressive slow decline. After every ischemic period, the pH adaptation curve showed a complex pattern reaching step-by-step lower minimum levels (7.28+/-0.14 during the first ischemic period, to 7.16+/-0.19 during the third ischemic period - P=0.003). PO(2) decreased rapidly at 90% in 5.0+/-1.2 min after every reperfusion. During ischemia, PCO(2) increased steadily at 1.6+/-0.1 mmHg per minute, with progressively incomplete removal after successive reperfusion, and progressive increase of maximal level (42+/-12 mmHg during the first ischemic period, to 53+/-23 mmHg during the third ischemic period - P=0.05). Myocardial oxygen, carbon dioxide, and pH show marked changes after repeated IWBC. Myocardial ischemia is not completely reversed by standardized reperfusions, as reflected by steady deterioration of PCO(2) and pH after each reperfusion. Progressive increase of reperfusion durations or direct monitoring of myocardial oxygenation could be advisable in cases of prolonged cross-clamping time.