Unmasking of a Giant Coronary Aneurysm by Chronic Total Coronary Occlusion Percutaneous Coronary Intervention Techniques.

A young female patient presenting with a non-ST-segment elevation myocardial infarction underwent invasive coronary angiography, revealing a total occlusion of the right coronary artery. During percutaneous coronary intervention with dual catheter access, a retrograde tip injection and peculiar retrograde wiring unmasked a giant coronary aneurysm, which noninvasive imaging confirmed.

The Search for an Outcome Variable That Measures Both Quality and Processes in Cardiac Surgery: Comparing the Quality Process Index and Mortality.

BACKGROUND: The translation of a large quantity of data into valuable insights for daily clinical practice is underexplored. A considerable amount of information is overwhelming, making it difficult to distill and assess quality and processes at the hospital level. This study contributes to this necessary translation by developing a Quality Process Index that summarizes clinical data to measure quality and processes. METHODS: The Quality Process Index was constructed to enable retrospective analyses of quality and process evolution from 2011 to 2021 for various surgery types in the Amsterdam Cardiosurgical Database (n = 5497). It is presented alongside mortality rates, which are the golden standard for quality measurement. The two outcome variables are compared as quality and process measurement options. RESULTS: Results showed that the mean Quality Process Index appeared rather stable, even though analysis of variance found that the mean Quality Process Index differed significantly over the years (p < 0.001). The 30-day and 120-day mortality rates appeared to fluctuate more, but interestingly, we failed to reject the null hypothesis of equal means. The Quality Process Index and mortality rates were statistically negatively correlated, and the extent of correlation was more pronounced with the 120-day mortality rate, as computed using the Pearson correlation coefficient r (30-day rQPI,30 = -0.07, p < 0.001 and 120-day mortality rates rQPI,120 = -0.12, p < 0.001). CONCLUSIONS: The Quality Process Index seeks to address the need to translate data for quality and process improvement in healthcare. While mortality remains the most impactful outcome measure, the Quality Process Index provides a more stable and comprehensive measurement of quality and process improvement or deterioration in healthcare. Therefore, the Quality Process Index as a quantification reinforces the understanding of the definition of quality and process improvement.

Thoracic aortopathy in Marfan syndrome overlaps with mechanisms seen in bicuspid aortic valve disease.

Background: Thoracic aortopathy is a serious complication which is more often seen in patients with Marfan syndrome (MFS) and patients with a bicuspid aortic valve (BAV) than in individuals with a tricuspid aortic valve (TAV). The identification of common pathological mechanisms leading to aortic complications in non-syndromic and syndromic diseases would significantly improve the field of personalized medicine. Objective: This study sought to compare thoracic aortopathy between MFS, BAV, and TAV individuals. Materials and methods: Bicuspid aortic valve (BAV; n = 36), TAV (n = 23), and MFS (n = 8) patients were included. Ascending aortic wall specimen were studied for general histologic features, apoptosis, markers of cardiovascular ageing, expression of synthetic and contractile vascular smooth muscle cells (VSMC), and fibrillin-1 expression. Results: The MFS group showed many similarities with the dilated BAV. Both patient groups showed a thinner intima (p < 0.0005), a lower expression of contractile VSMCs (p < 0.05), more elastic fiber thinning (p < 0.001), lack of inflammation (p < 0.001), and a decreased progerin expression (p < 0.05) as compared to the TAV. Other features of cardiovascular ageing differed between the BAV and MFS. Dilated BAV patients demonstrated less medial degeneration (p < 0.0001), VSMC nuclei loss (p < 0.0001), apoptosis of the vessel wall (p < 0.03), and elastic fiber fragmentation and disorganization (p < 0.001), as compared to the MFS and dilated TAV. Conclusion: This study showed important similarities in the pathogenesis of thoracic aortic aneurysms in BAV and MFS. These common mechanisms can be further investigated to personalize treatment strategies in non-syndromic and syndromic conditions.

Are acute type A aortic dissections atherosclerotic?

Background: Type A aortic dissections (TAAD) are devastating aortic complications. Patients with Marfan syndrome, a bicuspid aortic valve or a thoracic aortic aneurysm have an increased risk to develop a TAAD. These predisposing conditions are characterized by a histologically thin intimal layer and hardly any atherosclerosis. Little is known about the susceptibility for atherosclerosis in patients with a type A aortic dissection. Objective: We aim to systematically describe atherosclerotic lesions in TAAD patients. Materials and methods: A total of 51 patients with a TAAD (mean age 62.5 ± 10.8 years, 49% females) and 17 control patients (mean age 63 ± 5.5 years, 53% females) were included in this study. Cardiovascular risk factors were assessed clinically. All sections were stained with Movat pentachrome and hematoxylin eosin. Plaque morphology was classified according to the modified AHA classification scheme proposed by Virmani et al. Results: In the TAAD group thirty-seven percent were overweight (BMI > 25). Diabetes and peripheral arterial disease were not present in any of the patients. Fifty-nine percent of the patients had a history of hypertension. The intima in TAAD patients was significantly thinner as compared to the control group (mean thickness 143 ± 126.5 µm versus 193 ± 132 µm, p < 0.023). Seven TAAD patients had a normal intima without any form of adaptive or pathological thickening. Twenty-three TAAD patients demonstrated adaptive intimal thickening. Fourteen had an intimal xanthoma, also known as fatty streaks. A minority of 7 TAAD patients had progressive atherosclerotic lesions, 4 of which demonstrated pathological intimal thickening, 3 patients showed early fibroatheroma, late fibroatheroma and thin cap fibroatheroma. In the control group the majority of the patients exhibited progressive atherosclerotic lesions: three pathologic intimal thickening, two early fibroatheroma, six late fibroatheroma, one healed rupture and two fibrotic calcified plaque. Discussion: This study shows that TAAD patients hardly exhibit any form of progressive atherosclerosis. The majority of TAAD patients showcase non-progressive intimal lesions, whereas the control group mostly demonstrated progressive intimal atherosclerotic lesions. Findings are independent of age, sex, or the presence of (a history of) hypertension.

Anatomic Suitability for Branched Thoracic Endovascular Repair in Patients with Aortic Arch Pathological Features.

Background Endovascular repair has become a viable alternative for aortic pathological features, including those located within the aortic arch. We investigated the anatomic suitability for branched thoracic endovascular repair in patients previously treated with conventional open surgery for aortic arch pathological features. Methods and Results Patients who underwent open surgery for aortic arch pathological features at our institution between 2000 and 2018 were included. Anatomic suitability was determined by strict compliance with the anatomic criteria within manufacturers' instructions for use for each of the following branched thoracic stent grafts: Relay Plus Double-Branched (Terumo-Aortic), TAG Thoracic Branch Endoprosthesis (W.L. Gore & Associates), Zenith Arch Branched Device (Cook-Medical), and Nexus Stent Graft System (Endospan Ltd/Jotec GmbH). Computed tomography angiography images were analyzed with outer luminal line measurements. A total of 377 patients (mean age, 64±14 years; 64% men) were identified, 153 of whom had suitable computed tomography angiography images for measurements. In total, 59 patients (15.6% of the total cohort and 38.6% of the measured cohort) were eligible for endovascular repair using at least one of the devices. Device suitability was 30.9% for thoracic aneurysms, 4.6% for type A dissections, 62.5% for type B dissections, and 28.6% for other pathological features. Conclusions The anatomic suitability for endovascular repair of all aortic arch pathological features was modest. The highest suitability rates were observed for thoracic aneurysms and for type B dissections, of which repair included part of the aortic arch. We suggest endovascular repair of arch pathological features should be reserved for high-volume centers with experience in endovascular arch repair.

Correction to: Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The original version of this article unfortunately contained a mistake in the author name. The co-author name should be Frederikus A. Klok instead of Frederik A. Klok. The original article has been corrected.

Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The optimal antithrombotic therapy following mitral valve repair (MVr) is still a matter of debate. Therefore, we evaluated the rate of thromboembolic and bleeding complications of two antithrombotic prevention strategies: vitamin K antagonists (VKA) versus aspirin. Consecutive patients who underwent MVr between 2004 and 2016 at three Dutch hospitals were evaluated for thromboembolic and bleeding complications during three postoperative months. The primary endpoint was the combined incidence of thromboembolic and bleeding complications to determine the net clinical benefit of VKA strategy as compared with aspirin. Secondary objectives were to evaluate both thromboembolic and bleeding rates separately and to identify predictors for both complications. A total of 469 patients were analyzed, of whom 325 patients (69%) in the VKA group and 144 patients (31%) in the aspirin group. Three months postoperatively, the cumulative incidence of the combined end point of the study was 9.2% (95%CI 6.1-12) in the VKA group and 11% (95%CI 6.0-17) in the aspirin group [adjusted hazard ratio (HR) 1.6, 95%CI 0.83-3.1]. Moreover, no significant differences were observed in thromboembolic rates (adjusted HR 0.82, 95%CI 0.16-4.2) as well as in major bleeding rates (adjusted HR 1.89, 95%CI 0.90-3.9). VKA and aspirin therapy showed a similar event rate of 10% during 3 months after MVr in patients without prior history of AF. In both treatment groups thromboembolic event rate was low and major bleeding rates were comparable. Future prospective, randomized trials are warranted to corroborate our findings.

Antithrombotic strategy after bioprosthetic aortic valve replacement in patients in sinus rhythm: evaluation of guideline implementation.

OBJECTIVES: After elective aortic valve replacement, patients are at risk of developing valve thrombosis and systemic arterial thromboembolism. Current guidelines recommend antithrombotic therapy with aspirin or vitamin K antagonists (VKAs) during the first 3 months after the procedure, but have level 2 or 3 evidence. As a consequence, the most appropriate antithrombotic therapy is still a matter of debate. This retrospective study analysed all thromboembolic and bleeding complications in patients with either antiplatelet or anticoagulation therapy 1 year after bioprosthetic aortic valve replacement. METHODS: A total of 402 patients undergoing bioprosthetic aortic valve implantation at the VU University Medical Centre and subsequently treated at three regional hospitals were included. The individual duration of either VKAs (acenocoumarol) or aspirin was determined and related to thrombotic and bleeding events. Patients were followed and censored at 1 year postoperatively for survival, cerebral ischaemia, myocardial infarction, peripheral arterial embolism, and minor and major haemorrhages. RESULTS: A total of 24 thromboembolic complications and 31 bleeding episodes occurred. Multivariable analyses revealed that acenocoumarol caused more bleeding episodes (risk ratio [RR]: 8.41, 95% CI: 3.58-19.79) and a similar amount of thromboembolic events (RR: 1.2, 95% CI: 0.47-3.02) compared with aspirin. Prior use of acenocoumarol was found to be a risk factor for thromboembolic events (RR: 3.1, 95% CI: 1.31-7.19). Gender, dyslipidaemia, prior percutaneous coronary intervention, prior use of acenocoumarol and concomitant coronary artery bypass grafting were found to be predictors for bleeding events. CONCLUSIONS: In patients 1 year following bioprosthetic aortic valve replacement, acenocoumarol therapy was associated with a significant increased risk of bleeding events and no reduction in thromboembolic events compared with antiplatelet therapy. These findings support the recommendations of aspirin over VKAs as postoperative thromboprophylaxis.

Microcirculatory perfusion is preserved during off-pump but not on-pump cardiac surgery.

OBJECTIVE: This study investigated the perioperative course of microcirculatory perfusion in off-pump compared with on-pump surgery. Additionally, the impact of changes in systemic hemodynamics, hematocrit, and body temperature was studied. DESIGN: Prospective, nonrandomized, observational study. SETTING: Tertiary university hospital. PARTICIPANTS: Patients undergoing coronary artery bypass grafting with (n = 13) or without (n = 13) use of cardiopulmonary bypass. INTERVENTIONS: Microcirculatory measurements were obtained at 5 time points ranging from induction of anesthesia to ICU admission. MEASUREMENTS AND MAIN RESULTS: Microcirculatory recordings were performed with sublingual sidestream dark field imaging. Despite a comparable reduction in intraoperative blood pressure between groups, the perfused vessel density decreased more than 20% after onset of extracorporeal circulation but remained stable in the off-pump group. The reduction in microvascular perfusion in the on-pump group was further paralleled by decreased hematocrit and temperature. Although postbypass hematocrit levels and body temperature were restored to similar levels as in the off-pump group, the median microvascular flow index remained reduced after bypass (2.4 [2.3-2.7]) compared with baseline (2.8 [2.7-2.9]; p = 0.021). CONCLUSIONS: Microcirculatory perfusion remained unaltered throughout off-pump surgery. In contrast, microvascular perfusion declined after initiation of cardiopulmonary bypass and did not recover in the early postoperative phase.

Ten-year patterns in blood product utilization during cardiothoracic surgery with cardiopulmonary bypass in a tertiary hospital.

BACKGROUND: This retrospective analysis describes blood conservation strategies and overall consumption of red blood cells (RBCs), fresh-frozen plasma (FFP), and platelet (PLT) concentrates during nonaortic cardiac surgery with cardiopulmonary bypass (CPB) in a tertiary hospital over a 10-year period. STUDY DESIGN AND METHODS: Study variables of 6026 patients that underwent cardiac surgery between 2002 and 2011 were incorporated in the database and included hemoglobin (Hb), lowest temperature, CPB duration, 24-hour blood loss, fluid balance, and overall transfusion requirements. RESULTS: Between 2002 and 2011, the lowest intraoperative Hb levels and temperature increased from 8.5 ± 1.2 to 10.4 ± 1.4 g/dL and from 32 ± 2 to 34 ± 1°C, respectively. In addition to the steep decrease in the postoperative fluid balance over time, a reduction in 24-hour blood loss from 815 ± 588 mL (2002) to 590 ± 438 mL (2011) was observed. These changes were paralleled by a 28% reduction in overall RBC transfusion from 1443 units in 2002 to 1038 in 2011. While RBC transfusion decreased over time, there was no significant change in the use of FFP or PLT concentrate transfusion. The probability to receive RBC transfusion increased after cessation of aprotinin, but reduced after routine cell salvage in all operations. CONCLUSION: This institutional report shows a large reduction in blood loss and transfusion requirements in cardiac surgery over a 10-year period. This reduction is most probably attributed to structural cell salvage, reduced intraoperative fluid volumes, and the increase in the lowest intraoperative body temperature.

Intraoperative cell salvage is associated with reduced postoperative blood loss and transfusion requirements in cardiac surgery: a cohort study.

BACKGROUND: This study investigated whether implementation of cell salvage of shed mediastinal and residual blood in all patients undergoing low-to-moderate-risk cardiac surgery reduces the need for allogeneic red blood cell (RBC) transfusion compared to patients not subjected to cell salvage. STUDY DESIGN AND METHODS: This retrospective cohort study included patients undergoing low-to-moderate-risk cardiac surgery with cardiopulmonary bypass without (control; n = 531) or with cell salvage (n = 433; Autolog, Medtronic). Study endpoints, including 24-hour blood loss and RBC requirements, were evaluated using adjusted logistic regression. RESULTS: Baseline characteristics were similar between groups. The cell saver group received 568 ± 267 mL of autologous blood. Median number of allogeneic RBC transfusions was higher in the control group (2 [1-5]) compared with the cell salvage group (1 [0-3]; p < 0.001). There were no clinically relevant differences in postoperative coagulation test results between groups. The relative risk (RR) for postoperative RBC transfusion was reduced to 0.76 (95% confidence interval [CI], 0.70-0.83; p < 0.0001) in the cell salvage group. Moreover, patients in the cell salvage group had a lower chance for myocardial infarction (RR, 0.26; 95% CI, 0.08-0.91; p = 0.035), whereas the cell salvage group was associated with a higher probability for intensive care discharge within 24 hours after surgery (RR, 1.08; 95% CI, 1.02-1.14; p = 0.009). CONCLUSION: The use of cell salvage throughout the entire procedure reduces postoperative blood loss and allogeneic RBC transfusion. These findings advocate implementation of cell salvage in all patients undergoing on-pump cardiac surgery, irrespective of anticipated surgery-related blood loss.

Limitations of ranking lists based on cardiac surgery mortality rates.

BACKGROUND: Ranking lists are a common way of reporting performance in cardiac surgery; however, rankings have shown to be imprecise, yet the extent of this imprecision is unknown. We aimed to determine the precision of, and fluctuations in, ranking lists in the comparison of cardiac surgery mortality rates. METHODS AND RESULTS: Information on all adult cardiac surgery patients in all 16 cardiothoracic centers in The Netherlands from January 1, 2007, until December 31, 2009, was extracted from the database of the Netherlands Association for Cardio-Thoracic Surgery (n=46883). Ranks were assessed using crude and adjusted mortality rates, using a random effects logistic regression model. Risk adjustment was performed using the logistic EuroSCORE. Statistical precision of ranks was assessed with 95% confidence intervals. Additional analyses were performed for patients with isolated coronary artery bypass grafting. The ranking lists, based on mortality rates in 3 consecutive years, showed considerable reshuffling. When all data were pooled, the mean width of the 95% confidence intervals was 10 ranks using crude and 8 ranks using adjusted mortality rates. The large overlap of the confidence intervals across hospitals indicates that rank statistics were not materially different. Results were similar in the isolated coronary artery bypass grafting subgroup. CONCLUSIONS: Rankings are an imprecise statistical method to report cardiac surgery mortality rates and prone to (random) fluctuation. Hence, reshuffling of ranks can be expected solely due to chance. Therefore, we strongly discourage the use of ranking lists in the comparison of mortality rates.

Predicting outcome of rethoracotomy for suspected pericardial tamponade following cardio-thoracic surgery in the intensive care unit.

OBJECTIVES: Pericardial tamponade after cardiac surgery is difficult to diagnose, thereby rendering timing of rethoracotomy hard. We aimed at identifying factors predicting the outcome of surgery for suspected tamponade after cardio-thoracic surgery, in the intensive care unit (ICU). METHODS: Twenty-one consecutive patients undergoing rethoracotomy for suspected pericardial tamponade in the ICU, admitted after primary cardio-thoracic surgery, were identified for this retrospective study. We compared patients with or without a decrease in severe haemodynamic compromise after rethoracotomy, according to the cardiovascular component of the sequential organ failure assessment (SOFA) score. RESULTS: A favourable haemodynamic response to rethoracotomy was observed in 11 (52%) of patients and characterized by an increase in cardiac output, and less fluid and norepinephrine requirements. Prior to surgery, the absence of treatment by heparin, a minimum cardiac index < 1.0 L/min/m2 and a positive fluid balance (> 4,683 mL) were predictive of a beneficial haemodynamic response. During surgery, the evacuation of clots and > 500 mL of pericardial fluid was associated with a beneficial haemodynamic response. Echocardiographic parameters were of limited help in predicting the postoperative course, even though 9 of 13 pericardial clots found at surgery were detected preoperatively. CONCLUSION: Clots and fluids in the pericardial space causing regional tamponade and responding to surgical evacuation after primary cardio-thoracic surgery, are difficult to diagnose preoperatively, by clinical, haemodynamic and even echocardiographic evaluation in the ICU. Only absence of heparin treatment, a large positive fluid balance and low cardiac index predicted a favourable haemodynamic response to rethoracotomy. These data might help in deciding and timing of reinterventions after primary cardio-thoracic surgery.

Removal of aprotinin from low-dose aprotinin/tranexamic acid antifibrinolytic therapy increases transfusion requirements in cardiothoracic surgery.

This retrospective study investigated whether withdrawal of aprotinin from combined low-dose aprotinin/tranexamic acid (TXA) antifibrinolytic therapy altered postoperative blood loss and transfusion requirements in patients undergoing cardiothoracic surgery employing cardiopulmonary bypass (CPB). The study included data from patients receiving a combination of low-dose aprotinin (2×10(6) KIU in CPB prime; n=615) and 2000 mg TXA or patients receiving TXA only (n=587). In both groups, TXA was given after protamine administration. Study endpoints were blood loss, transfusion requirements and reoperation. There were no differences in EuroSCORE, CPB time, antiangial medication and baseline coagulation parameters between groups. There were more males in the TXA group (85%) as compared to the TXA+aprotinin group (77%; P=0.02). Postoperative blood loss (0.80±0.69 vs. 0.66±0.52 l; P=0.001) and transfusion of fresh frozen plasma (0.6±0.7 vs. 0.4±0.6 U; P<0.001), packed cells (3.9±5.5 vs. 2.7±3.3 U; P<0.001) and platelets (0.7±0.6 vs. 0.5±0.6 U; P<0.001) was higher in the TXA group than in patients receiving combined therapy, respectively. There were more reoperations for bleeding in the TXA group (53 vs. 34, respectively; P=0.03) with similar mortality and deterioration in glomerular filtration rate. In conclusion, withdrawal of aprotinin from combined antifibrinolytic therapy is associated with increased blood loss, transfusion requirements and reoperations.

The association of hemodilution and transfusion of red blood cells with biochemical markers of splanchnic and renal injury during cardiopulmonary bypass.

BACKGROUND: Hemodilution is the main cause of a low hematocrit concentration during cardiopulmonary bypass. This low hematocrit may be insufficient for optimal tissue oxygen delivery and often results in packed cell transfusion. Our objective in this study was to find a relationship between intraoperative hematocrit and allogeneic blood transfusion on release of postoperative injury markers from the kidneys and the splanchnic area. METHODS: Fifty consecutive patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were included. Systemic tissue hypoxia was assessed by lactate concentrations. Kidney and splanchnic ischemia were assessed by the measurement of N-acetyl-beta-D-glucosaminidase (NAG) and intestinal fatty acid binding protein (IFABP) in urine. Patients were retrospectively placed into groups according to their lowest hematocrit concentration on bypass (<24% or >or=24%). RESULTS: The intraoperative lactate and the postoperative NAG and IFABP concentrations were higher in the low hematocrit group (<24%) than in the high hematocrit group (>or=24%; P < 0.05). Low hematocrit correlated with higher lactate concentrations (R(2) = 0.150, P < 0.01) and with higher NAG concentrations (R(2) = 0.138, P < 0.01) and IFABP concentrations (R(2) = 0.107, P < 0.01) postoperatively. Transfusion of packed cells during cardiopulmonary bypass correlated with higher lactate (R(2) = 0.089, P < 0.05), NAG (R(2) = 0.431, P < 0.01), and IFABP concentrations (R(2) = 0.189, P < 0.01). CONCLUSIONS: The results support the concept that hemodilution below an intraoperative hematocrit of 24% and consequently transfusion of red blood cells is related to release of injury markers of the kidneys and splanchnic area.

Mechanisms of pulmonary dysfunction after on-pump and off-pump cardiac surgery: a prospective cohort study.

BACKGROUND: Pulmonary dysfunction following cardiac surgery is believed to be caused, at least in part, by a lung vascular injury and/or atelectasis following cardiopulmonary bypass (CPB) perfusion and collapse of non-ventilated lungs. METHODS: To test this hypothesis, we studied the postoperative pulmonary leak index (PLI) for 67Ga-transferrin and (transpulmonary) extravascular lung water (EVLW) in consecutive patients undergoing on-pump (n = 31) and off-pump (n = 8) cardiac surgery. We also studied transfusion history, radiographs, ventilatory and gas exchange variables. RESULTS: The postoperative PLI and EVLW were elevated above normal in 42 and 29% after on-pump surgery and 63 and 37% after off-pump surgery, respectively (ns). Transfusion of red blood cell (RBC) concentrates, PLI, EVLW, occurrence of atelectasis, ventilatory variables and duration of mechanical ventilation did not differ between groups, whereas patients with atelectasis had higher venous admixture and airway pressures than patients without atelectasis (P = 0.037 and 0.049). The PLI related to number of RBC concentrates infused (P = 0.025). CONCLUSION: The lung vascular injury in about half of patients after cardiac surgery is not caused by CPB perfusion but by trauma necessitating RBC transfusion, so that off-pump surgery may not afford a benefit in this respect. However, atelectasis rather than lung vascular injury is a major determinant of postoperative pulmonary dysfunction, irrespective of CPB perfusion.

The impact of heparin-coated circuits on hemodynamics during and after cardiopulmonary bypass.

This study was performed to investigate if heparin-coated extracorporeal circuits can reduce the systemic inflammatory reaction with the subsequent release of vasoactive substances during and after cardiopulmonary bypass. Fifty-one patients scheduled for coronary artery bypass grafting were perfused with either a heparin-coated or an uncoated circuit. During bypass the mean arterial pressure was maintained as near as possible to 60 mm Hg. Mediators for inflammation, hemodynamic, and oxygen parameters were determined during and after bypass. To reach the target mean arterial pressure in the first hour of bypass the pump flow in the uncoated group had to be increased (P<0.05), consequently the systemic vascular resistance index decreased (P<0.05). After bypass more inotropic support was necessary in this group to reach this pressure. In the coated group less bradykinin, complement activation, and elastase was generated during bypass (P<0.05). The results of this study suggest that heparin coating not only improves biocompatibility, but also ameliorates the hemodynamic instability during and after bypass.

Pressure-diameter relationship in the human greater saphenous vein.

BACKGROUND: Compliance of artificial and autologous vascular grafts is related to future patency. We investigated whether differences in compliance exist between saphenous vein grafts derived from the upper or lower leg, which might indicate upper or lower leg saphenous vein preference in coronary artery bypass surgery. Furthermore, the effect of perivenous application of fibrin glue on mechanical vein wall properties was studied to evaluate its possible use as perivenous graft support. METHODS: Vein segments (N = 10) from upper or lower leg saphenous vein grafts were collected for histopathologic examination and smooth muscle cell/extracellular matrix (SMC/ECM) ratio was calculated. This ratio is suggested to be related with vascular elastic compliance. In a second group vein graft segments (N = 6) from upper and lower leg were placed in an in vitro model generating stepwise increasing static pressure up to 150 cm H(2)O. Outer diameter was measured continuously with a video micrometer system. Distensibility was calculated from the pressure-diameter curves. A third group of vein graft segments (N = 7) was pressurized after fibrin glue application to prevent overdistension, and studied in the same setup. RESULTS: Vein segments from the lower leg demonstrated a consistent higher relative response compared with the upper leg saphenous vein graft (0.9176 +/- 0.03993 vs 0.5245 +/- 0.02512). Both reach a plateau in the high-pressure range (> 100 cm H(2)O). A significant difference in in vitro distensibility between upper and lower leg saphenous vein was only found at a pressure of 50 cm H(2)O (p < 0.05). With fibrin glue, support overdistension is prevented as revealed by the maximum relative response between fibrin glue supported upper and lower leg saphenous vein segments (0.4080 +/- 0.02464 vs 0.582 +/- 0.051), and no plateau is reached in the pressure range up to 150 cm H(2)O. CONCLUSIONS: No upper or lower leg saphenous vein preference could be deduced from the differences in pressure-diameter response due to loss of distensibility (and thus of compliance) in the high-pressure range. Fibrin glue effectively prevents overdistension and preserves some distensibility in the high-pressure range in both the upper and lower leg saphenous vein. This might provide a basis for clinical application of perivenous support.