Ten-year results of aortic valve replacement with first-generation Mitroflow bioprosthesis: is early degeneration a structural or a technical issue?

OBJECTIVES: Concerns have been raised about the durability of the first-generation Mitroflow aortic bioprosthesis (model 12 A-LX) due to the lack of anticalcification treatment. This study reflects a 10-year experience with this prosthesis for aortic valve replacement. METHODS: From June 2003 to May 2012, the Mitroflow prosthesis was used for aortic valve replacement in 510 patients, of whom only 467 with complete clinical follow-up were included for analysis. Study end-points were survival and incidence of structural valve degeneration (SVD). Analysis of SVD was based on cumulative incidence function and competing-risk Cox regression. RESULTS: The mean patient age was 76.4 ± 6.1 years. Valve sizes from 23 to 25 were used in 70.4%, whereas sizes from 19 to 21 were used in only 19.2%, thereby avoiding patient-prosthesis mismatch in 89.1%. Within a median follow-up time of 6.6 years (interquartile range 4.4), a cumulative 2375 patient-years, the survival rate was 86.2%, 67.3% and 33.3% at 1, 5 and 10 years, respectively. The cumulative incidence of SVD, with death as a competing risk, was 0%, 0.7% and 6.2% at 1, 5 and 10 years, respectively. Only age <75 years tended to affect the late hazard of SVD (hazard ratio 0.50, 95% confidence interval 0.23-1.08, P = 0.08), regardless of valve-specific issues. CONCLUSIONS: The data do not support the concerns about early accelerated structural degeneration of the first-generation Mitroflow bioprosthesis used for aortic valve replacement in patients older than 75 years. We postulate that limiting the number of small prostheses using a proper implantation technique has enhanced the reduction in risk of significant patient-prosthesis mismatch as the main determinant of early SVD.

Low target-INR anticoagulation is safe in selected aortic valve patients with the Medtronic Open Pivot mechanical prosthesis: long-term results of a propensity-matched comparison with standard anticoagulation.

OBJECTIVES: To investigate the long-term results of a low international normalized ratio (INR)-anticoagulation program in selected patients after aortic valve replacement (AVR) with the Medtronic Open Pivot mechanical heart valve (OPMHV). METHODS: From January 1993 to December 2012, 909 OPMHV valves were used for single AVR. Patients with preserved sinus rhythm and left ventricular function (Low-INR, n = 552), were managed to an INR of 1.5-2.5 and compared to patients (Standard-INR, n = 357) treated with standard anticoagulation (INR 2.5-3.5). Long-term outcome was analysed for survival and valve-related events, on propensity score matched pairs of 169 patients/group. RESULTS: Within a follow-up cumulating 3096 patient-years, 10- and 15-year survival was significantly better for Low-INR patients: 79% and 63% vs 63% and 34% ( P < 0.001). Multivariate analysis of late mortality identified older age [odds ratio (OR) = 1.05], chronic pulmonary disease (OR = 1.90) and coronary artery disease (OR = 1.57) as patient-related risk factors, and erratic INR (OR = 2.57) as anticoagulation-related factor. The linearized thromboembolic rate was 0.72%/patient-year in Low-INR patients, vs 0.87%/patient-year in Standard-INR patients ( P = 0.59), revealing INR variability as sole predictor (OR 3.54, 95% confidence interval (CI) 1.20-10.51, P = 0.022). The linearized bleeding incidence was respectively 0.61%/patient-year and 1.21%/patient-year for Low-INR and Standard-INR patients ( P = 0.04), retaining older age (OR 1.06, 95% CI 1.02-1.12, P = 0.009), hypertension (OR 2.06, 95% CI 1.00-4.25, P = 0.05) and erratic INR (OR 9.83, 95% CI 5.21-18.56, P < 0.001) as independent risk factors. CONCLUSIONS: This study demonstrated that application of an anticoagulation regimen, aiming a low INR, individualized to selected aortic OPMHV patients, is safe and effective over more than 20 years, without increasing the thromboembolic complication rate while lowering the haemorrhagic events. However, INR variability remains worrisome because of its deleterious effect on outcome.

Minimally Invasive Repair of Mitral Valve Prolapse and Concomitant Atrial Fibrillation Ablation in a Heart Transplant.

Significant mitral valve disease with atrial fibrillation after heart transplantation is unusual. We report the diagnosis and minimally invasive surgical treatment 17 years after transplantation, in which mitral valve repair together with left atrial ablation was performed, resulting in a satisfying clinical and echocardiographic improvement.

Twenty-year single-center experience with the medtronic open pivot mechanical heart valve.

BACKGROUND: Since May 1992 the Medtronic Open Pivot mechanical heart valve has been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of the valve. METHODS: Between May 1992 and December 2011 a total of 1,520 valves was inserted into 1,382 consecutive patients (1,012 aortic, 473 mitral, 26 tricuspid, 9 pulmonary). The mean age of the patients was 61±13.2 years. Preoperatively, 65% of the patients were in New York Heart Association (NYHA) class III or greater. Frequent comorbidities included atrial fibrillation (n=419), coronary disease (n=357), and diabetes (n=255). The 99% complete follow-up totaled 10,527 patient-years (range 12 to 244 months). RESULTS: Ninety-day mortality was 5.2% (n=73, 8 valve related). Of the 550 total deaths, 240 were cardiac and 56 valve related. Multivariate analysis selected age, NYHA III or greater, concomitant coronary revascularization, and respiratory insufficiency as risk factors for death. Renal failure was considered a risk factor in the aortic and atrial fibrillation in the mitral subgroup. Erratic international normalized ratio (INR), NYHA class III or greater, and non-sinus rhythm were risk factors for thromboembolism; likewise redo operations in the aortic subgroup. Erratic INR and age were risk factors for bleeding as were over-coagulation and coronary revascularization in the aortic subgroup and redo operations and renal failure in mitral patients. CONCLUSIONS: This 20-year experience demonstrated excellent clinical outcomes with no structural valve failure. Odds ratio defined aortic patients as the lowest risk for adverse events. By contrast atrial fibrillation and elderly age, in combination with instable anticoagulation, yielded the worst long-term results.

Reappraisal of a single-centre policy on the contemporary surgical management of active infective endocarditis.

OBJECTIVES: We studied a contemporary cohort of adult patients treated surgically for infective endocarditis (IE) in order to evaluate the surgical approach and predictors of outcomes, in relation to the intercurrent adaptation of the 2006 ACC/AHA guidelines. METHODS: One hundred and eighty-six consecutive patients operated on for active IE from August 1999 to September 2012 were reviewed retrospectively. Clinical presentation, surgical management and outcomes in the two study periods before and after January 2007 were compared (Period 1: n = 95 and Period 2: n = 91). RESULTS: The mean (SD) follow-up was 4.3 (3.8) years and was 99.5% complete. Patients in Period 2 had more frequently associated coronary artery disease (31 vs 18%, P = 0.06), while the microbiology revealed more Staphylococcus species (43 vs 26%, P = 0.02), predominantly Staphylococcus aureus (31 vs 19%; P = 0.07), and less culture-negative cases (7 vs 17%; P = 0.05). The median delay between diagnosis and surgery was 7 days in Period 2 compared with 14 days in Period 1 (P = 0.001). Surgery in Period 2 included more root replacements for aortic valve endocarditis (11 vs 2%; P = 0.02) and mitral valve repairs (18 vs 5%; P = 0.01), while the use of homografts for aortic valve endocarditis was almost abandoned (1 vs 15%; P = 0.001). Hospital mortality was 13% and did not change significantly over both periods (P = 0.66). The independent predictors of hospital mortality were age (P = 0.03), female gender (P = 0.02), previous cardiac surgery (P = 0.02), preoperative serum creatinine level >2 mg/dl (P = 0.05), S. aureus infection (P = 0.02), emergent or salvage operation (P = 0.001) and concomitant coronary artery bypass grafting (P = 0.03). The 1-, 3-, 5- and 10-year survival were 84, 72, 64 and 57%, respectively. Late survival was negatively influenced by S. aureus endocarditis (P < 0.001) and peripheral vascular disease (P = 0.03), whereas associated coronary artery disease (P = 0.07) had a strong impact. CONCLUSIONS: Adaptation of the 2006 ACC/AHA guidelines in the contemporary management of IE led to a shorter interval between diagnosis and surgery. Despite a more extensive and earlier operative approach, IE caused by S. aureus still remains a major determinant of early and late outcomes.

Twenty years' single-center experience with mechanical heart valves: a critical review of anticoagulation policy.

BACKGROUND AND AIM OF THE STUDY: Since January 1990, a variety of mechanical valves (St. Jude Medical, CarboMedics, ATS Medical) have been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of those mechanical valves, and to challenge the anticoagulation policy employed over the years. METHODS: Between January 1990 and December 2008, a total of 2,108 mechanical valves was inserted into 1,887 consecutive patients (1,346 aortic, 725 mitral, 27 tricuspid, 10 pulmonary). The mean age of the patients was 63 +/- 13.2 years, and the majority (61%) were males. Preoperatively, 71% the patients were in NYHA class > or = III (average 3.01). The most frequent comorbidities included: atrial fibrillation (n = 594), coronary disease (n = 567) and diabetes (n = 398). The follow up (99% complete) totaled 13,721 patient-years (pt-yr), and ranged from 12 to 241 months (average 84 months). RESULTS: In-hospital mortality was 5.2% (n = 98, 14 valve-related). Of the 629 late deaths, the majority were cardiac (n = 276). Survival (Kaplan-Meier estimation) was significantly better for aortic valve patients compared to mitral or multiple valve replacement (Mantel-Cox, p < 0.0001). The overall linearized incidences (as %/pt-yr) were: valve thrombosis 0.31, thromboembolism 1.08, and bleeding 0.91. However, as repeated events occurred in several patients, the hazard function was not constant. Multivariate analysis (Cox regression model) showed age > 70 years (p < 0.0001), NYHA class > or = III (p < 0.0001), non-sinus rhythm (p = 0.001), concomitant coronary artery bypass grafting (p = 0.008) and higher International Normalized Ratio (INR) values (p = 0.013) as significant risk factors for death, with a trend for redo operations (p = 0.052). Multivariate analysis found variable INR, non-sinus rhythm and NYHA class > II as significant risk factors for thromboembolism, while long-acting coumadin and NYHA class > II were significant risk factors for bleeding. CONCLUSION: This 20-year experience demonstrated excellent clinical outcomes for patients with mechanical prostheses, with no valve structural failure and an acceptable incidence of adverse events. INR values between 2-2.5 for aortic valve patients, and 3-3.5 for mitral valve patients, yielded the fewest major adverse events.

Fatal acute pulmonary injury associated with everolimus.

OBJECTIVE: To report a case of fatal alveolar hemorrhage associated with the use of everolimus in a patient who underwent a solid organ transplant. CASE SUMMARY: In a 71-year-old cardiac transplant patient, cyclosporine was replaced with everolimus because of worsening renal function. Over the following weeks, the patient developed nonproductive cough and increasing dyspnea. His condition deteriorated to acute respiratory failure with hemoptysis, requiring hospital admission. Bilateral patchy alveolar infiltrates were apparent on chest X-ray and computed tomography. Cardiac failure was ruled out and empiric antimicrobial therapy was initiated. Additional extensive workup could not document opportunistic infection. Everolimus was discontinued and high-dose corticosteroid therapy was initiated. Despite this, the patient required invasive mechanical ventilation and died because of refractory massive hemoptysis. Autopsy revealed diffuse alveolar hemorrhage. DISCUSSION: Everolimus is a mammalian target of rapamycin inhibitor approved for use as an immunosuppressant and antineoplastic agent. Its main advantage over calcineurin inhibitors (tacrolimus and cyclosporine) is a distinct safety profile. Although it has become clear that everolimus induces pulmonary toxicity more frequently than initially thought, most published cases thus far represented mild and reversible disease, and none was fatal. Here, we report a case of pulmonary toxicity developing over weeks following the introduction of everolimus, in which a fatal outcome could not be prevented by drug withdrawal and corticosteroid treatment. The association of everolimus and this syndrome was probable according to the Naranjo probability scale. CONCLUSIONS: This case indicates that with the increasing use of everolimus, clinicians should be aware of the rare, but life-threatening manifestation of pulmonary toxicity.

Ten years single-centre experience with intra-aortic balloon pump.

OBJECTIVES: The objective of this study was to investigate the patient characteristics and outcomes in 1406 patients undergoing intra-aortic balloon pump (IABP) counterpulsation. METHODS: Between 1998 and 2008, 1406 consecutive patients were recorded in a prospective database. Based on the main clinical indication for IABP use, we defined 3 groups: group A, 630 cases of coronary ischaemia or infarction without serious left ventricular (LV) dysfunction; group B, 466 patients with left ventricular failure or cardiogenic shock; group C, 310 patients where IABP was used for miscellaneous procedures such as weaning from cardiopulmonary bypass or during high-risk angioplasty or surgery. RESULTS: Global mortality was 28% (n = 390), with a significant difference between group A (15%, n = 95) and group B (41%, n = 191) (P < 0.001). Mortality in group C was 34% (n = 104). Most insertions were done in the catheterization laboratory (n = 943) with subsequent mortality of 23% whereas 199 balloons were inserted in the operation room with 34% mortality. 170 balloons inserted in the intensive care unit resulted in 46% mortality (P < 0.001). Major IABP-induced complications were 6.8% with no statistical differences between the three groups. Advanced age, left ventricular failure and low BMI were identified as prognostic risk factors for early mortality. CONCLUSIONS: IABP deployed at an early clinical stage yields the best results, especially for acute coronary patients with preserved LV function whereas LV failure and late insertion result in worse outcome.

Fifteen years' single-center experience with the ATS bileaflet valve.

BACKGROUND AND AIM OF THE STUDY: Since its introduction in May 1992, the bileaflet ATS Open Pivot valve has been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 15-year clinical results of these implanted ATS valves. METHODS: Between May 1992 and December 2005, a total of 1,160 ATS valves (749 aortic, 381 mitral, 21 tricuspid, nine pulmonary) was implanted in 1,047 consecutive patients (655 males, 392 females; mean age 62.1 +/- 12.4 years). Preoperatively, 75% of the patients were in NYHA class III or higher (mean 3.1). The most frequent comorbidities included atrial fibrillation (n = 381), coronary disease (n = 288) and diabetes (n = 172). RESULTS: The mean follow up was 78 months (range: 24-183 months); the total follow up was 6,887 patient-years (pt-yr) and was 99.8% complete. In-hospital mortality was 4% (n = 43; three valve-related). Survival (Kaplan-Meier) at five and 10 years was significantly better for aortic than for mitral valve patients (84% and 65% versus 75% and 41%, respectively) (Mantel-Cox, p < 0.001). A log rank analysis detected no statistical difference in the incidence of thromboembolism (p = 0.182) or bleeding (p = 0.375) between both groups. The overall linearized incidences were: thromboembolism 1.08%/pt-yr; bleeding 0.91%/pt-yr; endocarditis 0.22%/pt-yr; paravalvular leakage 0.33%/pt-yr; and valve thrombosis 0.21%/pt-yr. Multivariate analysis (Cox regression) indicated age > 70 years (p < 0.0001), NYHA class > or = III (p < 0.0001), non-sinus rhythm (p = 0.001), concomitant CABG (p = 0.008) and higher INR values (p = 0.013) to be significant risk factors for death. CONCLUSION: This 15-year experience with the ATS bileaflet prosthesis showed excellent clinical outcomes for patients, with no structural failure and an acceptable incidence of adverse events.

Short-term systolic and diastolic ventricular performance after surgical ventricular restoration for dilated ischemic cardiomyopathy.

OBJECTIVE: Based on the adverse relationship between left ventricular (LV) remodeling and clinical outcome in ischemic cardiomyopathy, surgical ventricular restoration (SVR) is proposed as a valuable adjunct procedure. This study reports on the short-term clinical and hemodynamical performance of SVR. METHODS: Using end-systolic LV volume as indication for SVR, 78 patients with ischemic cardiomyopathy are divided in two groups: group 1 comprised 55 patients treated by coronary revascularization and mitral annuloplasty, group 2 comprised 23 patients undergoing additional SVR. Hemodynamic investigation included echocardiographic assessment of systolic and diastolic function. Clinical follow-up focused on survival and functional status with exercise performance. RESULTS: Both surgical approaches resulted in improvement of NYHA class (2.9-1.6 in group 1; 3.3-1.5 in group 2, p<0.001), achieving similar exercise performance (peak VO2 13.7 vs 15.4 ml/kgmin in groups 1 and 2, p=0.25) and plasma BNP values (group 1: 1350 pg/ml and group 2: 767 pg/ml, p=0.23). SVR provided additional benefit as patients basically had a worse NYHA class (2.9 in group 1 vs 3.3 in group 2, p=0.03). Within mean follow-up of 20 months, survival rate was 84% in group 1 and 74% in group 2 (p=0.11), including operative mortality of 7% and 13% (p=0.42). Through effective volume reduction (LVEDVI 41%; LVESVI 49%) systolic function improved immediately after SVR (LVEF 27-39% in group 2, p<0.05). Worsening of diastolic function was specifically observed after SVR within the first year (E/A-ratio 1.38-1.74 cm/s, p=0.02). Recurrent mitral regurgitation (p=0.004) and secondary remodeling (p=0.01) were major determinants of decreasing LV compliance. Clinical outcome in terms of cardiac events and survival was compromised by restrictive diastolic function (p=0.02) and increased LV volumes (p=0.04). CONCLUSION: SVR in addition to coronary revascularization and restrictive mitral annuloplasty results in significant clinical improvement in selected patients with advanced ischemic heart disease and severely dilated ventricles. SVR entails immediate improvement of systolic function, which remains sustained during short-term follow-up. Serial assessment of diastolic function is mandatory as LV compliance seems more sensitive to early changes induced by recurrence of mitral regurgitation and secondary ventricular dilation. Moreover, worsening of diastolic dysfunction should be timely recognized because of its adverse clinical impact.

Stentless and stented aortic valve replacement in elderly patients: Factors affecting midterm clinical and hemodynamical outcome.

OBJECTIVE: To report on the midterm results of aortic valve replacement (AVR) with stented and stentless bioprosthesis in an elderly population by analyzing the factors affecting survival and hemodynamical performance. METHODS: In a retrospective study, 145 patients with a Toronto stentless prosthesis are compared with 110 patients with a stented Carpentier-Edwards valve. The 5- to 10-year clinical outcome, transprosthetic gradients, and early and late left ventricular mass (LVM) regression are analyzed in view of specific prosthesis- and patient-related factors. RESULTS: Actuarial survival at 5 years is 82% after stentless AVR versus 68% after stented AVR (p < 0.001) in elderly patients. However, there was no difference in survival at 8 years, being 55.9% and 59.5%, respectively. Univariate analysis revealed that advanced age at the time of operation, NYHA class IV, use of a stented xenograft, presence of patient-prosthesis mismatch (PPM) (IEOA < or = 0.85 cm2/m2), and severe preoperative left ventricular (LV) hypertrophy (LVMI > 180 g/m2) affected survival adversely. But multivariate analysis determined only age, NYHA class IV and excessive LV hypertrophy as independent predictors of late mortality. Stented and stentless xenografts were equally effective in terms of transprosthetic gradients and LVMI regression. The use of a stentless valve significantly reduced the occurrence of PPM (18% vs 41%, p < 0.01). Early LVMI regression at 1 year was optimized by the avoidance of PPM, indicated by a higher absolute (43.7+/-28.3 g/m2 vs 58.6+/-33.8 g/m2, p = 0.003) and relative (25.0+/-12.7% vs 31.4+/-14.9%, p=0.004) mass regression. However, late LV remodeling was predominantly affected by systemic hypertension and severe preoperative LV hypertrophy, resulting in the incomplete LVMI resolution in 61.3% and 66.7% of these patients, respectively. CONCLUSION: In elderly patients, aortic valve replacement appears to be equally effective with a stentless or stented bioprosthesis. Midterm clinical outcome is mainly determined by patient-related factors such as age, advanced NYHA class, and severity of preoperative LV hypertrophy. Regarding post-AVR left ventricular remodeling, patient-prosthesis mismatch influences the early phase, whereas arterial hypertension affects the late regression more. However, the left ventricular remodeling is continuously compromised by the preoperative presence of excessive hypertrophy, despite the efficacy of the aortic valve replacement.

Aortic valve replacement with Toronto SPV in elderly patients: 10-year results.

A retrospective assessment of clinical and echocardiographic variables was performed in 145 patients who received a Toronto SPV aortic valve replacement. The majority (90%) of these elderly patients (mean age, 75.5 +/- 7.4 years) were preoperatively in New York Heart Association class III-IV. Operative mortality was 4.8%. Follow-up was complete up to 10 years and revealed few valve-related complications: thromboembolism (7), bleeding (4), and prosthesis dysfunction necessitating reoperation (3). Late mortality was cardiac-related in 11.7% and noncardiac-related in 17.2%. Actuarial survival was 83% at 5 years and 63% at 8 years. Echocardiography showed low transvalvular gradients (peak, 17.5 +/- 7.5 mm Hg; mean, 9.2 +/- 4.2 mm Hg) resulting in a significant reduction in left ventricular mass index during the first 3 years. Independent of the transprosthetic gradient, left ventricular mass index tended to increase again beyond the 5th year, which correlated positively with the presence of arterial hypertension in this older population. The Toronto SPV bioprosthesis offers an aortic valve substitute with excellent long-term hemodynamics, resulting in significant early left ventricular mass regression. Considering the limitations of this selected elderly population, the clinical outcome and survival up to 10 years are encouraging, with few observed valve-related events.

Lower-intensity anticoagulation for mechanical heart valves: a new concept with the ATS bileaflet aortic valve.

BACKGROUND AND AIM OF THE STUDY: The design of the bileaflet ATS mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of blood at the pivot area seen using three-dimensional computational fluid dynamics modeling may make the valve less vulnerable for clot formation in patients without major thromboembolic risk factors. METHODS: Between January 1993 and June 1999, the ATS valve was implanted in the aortic position in 286 consecutive patients. Patients were allocated prospectively to two groups: group 1 comprised patients in regular sinus rhythm with good left ventricular (LV) function (n = 144); group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (n = 142). The anticoagulation regime in group 1 was to achieve an INR of 1.5-2.5, rather than to maintain INR strictly at 2.5-3.5 for mechanical valves (as in group 2). RESULTS: Follow up was 99% complete and ranged from 50 to 120 months. Survival (Kaplan-Meier) was respectively 95% and 90% and 90% and 83% at 2 and 5 years in favor of group 1 (p = 0.0055). Multivariate analysis selected advanced age, poor LV function and 'erratic' INR as risk factors for death. Log rank analysis failed to detect any statistical difference in thromboembolism. Bleeding occurred more frequently in group 2 (p = 0.018); independent risk factors for bleeding were the presence of aspirin (p = 0.0164) and advanced age (p = 0.02). CONCLUSION: The excellent group 1 data and outcome encouraged continuation of the low-intensity anticoagulation regime, and should be regarded as a new concept for the treatment of mechanical valve patients.

Lower anticoagulation for mechanical heart valves: experience with the ATS bileaflet valve.

BACKGROUND: The design of the bileaflet ATS (ATS Medical Inc., Minneapolis, USA) mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of the blood at the pivot area was observed using 3-D computational fluid dynamics modelling. This phenomenon could make the valve less vulnerable to clot formation in patients without major thromboembolic risk factors. METHODS: From January 1993 to June 1999, 286 consecutive patients had the ATS valve inserted in the aortic position. Patients were divided into two groups. Group 1 comprised all patients in regular sinus rhythm with good left ventricular function (144 patients). Group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (142 patients). The anticoagulation regime in group 1 was used to obtain an international normalised ratio (INR) between 1.5 and 2.5. This contrasts with our regular aim to maintain the INR strictly between 2.5 and 3.5 for all mechanical valves, as achieved in group 2. RESULTS: The follow-up period (99% completeness) ranged from 18 to 84 months. Survival (Kaplan-Meier) was 97 and 98% and 92 and 81% at 1 and 5 years in group 1 and group 2, respectively (P = 0.12). Log rank analysis failed to detect a statistical difference in thromboembolism or bleeding between both groups (P > 0.05). However, trends were in favour of group 1. Univariate analysis selected poor ventricular function and an 'erratic' INR value (P = 0.002) as risk factors for death. The sole independent risk factor for bleeding was the use of aspirin (P = 0.025). CONCLUSIONS: The excellent group 1 data and outcome encouraged us to continue our low intensive anticoagulation regime and perhaps should be regarded as a new concept for treatment of selected mechanical valve patients.

Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation.

OBJECTIVE: To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects. DESIGN: Prospective, controlled study. SETTING: An eight-bed, cardiac-surgical intensive care unit at a university hospital. PATIENTS: Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation. INTERVENTIONS: Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3). MEASUREMENTS AND MAIN RESULTS: No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed. CONCLUSIONS: Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.