Predicting Transfusion Requirements During Extracorporeal Membrane Oxygenation.

OBJECTIVE: Patients requiring extracorporeal membrane oxygenation (ECMO) have a well-known bleeding risk and the potential for experiencing possibly fatal thromboembolic complications. Risk factors and predictors of transfusion requirements during ECMO support remain uncertain. The authors hypothesized that compromised organ function immediately before ECMO support will influence transfusion requirements. DESIGN: A prospective observational study. SETTING: A tertiary, single-institutional university hospital. PARTICIPANTS: The study included 40 adult patients requiring ECMO for intractable cardiac and respiratory failure between July 2010 and December 2012. Blood samples were taken before initiation of ECMO (baseline), after 24 and 48 hours on ECMO, and 24 hours after termination of ECMO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Independent of veno-arterial or veno-venous support, 26% of patients required≥2 packed red blood cells per day (PRBC/d) and 74% of patients required<2 PRBC/d during ECMO. Requirements of≥2 PRBC/d during ECMO support were associated with higher creatinine levels and lower prothrombin times (PT, %) at baseline and with impaired platelet function after 24 hours on ECMO. Platelet function, activated by thrombin receptor-activating peptide stimulation, decreased by 30% to 40% over time on ECMO. Receiver operating characteristic curve analysis showed cut-off values for creatinine of 1.49 mg/dL (sensitivity 70%, specificity 70%; area under the curve [AUC] 0.76, 95% confidence interval [CI] 0.58-0.94), for PT of 48% (sensitivity 80%, specificity 59%; AUC 0.69, 95% CI 0.50-0.87), and for thrombin receptor-activating peptide (TRAP) 32 U (sensitivity 90%, specificity 68%; AUC 0.76, 95% CI 0.59-0.93). CONCLUSIONS: The results of this study demonstrated that increased creatinine levels and lower PT before ECMO and secondary impaired platelet function significantly increased transfusion requirement.

Extracorporeal membrane oxygenation induces short-term loss of high-molecular-weight von Willebrand factor multimers.

BACKGROUND: High-molecular-weight (HMW) von Willebrand factor (vWF) multimers are crucial for primary hemostasis. Increased shear stress from ventricular assist devices can provoke premature degradation of HMW vWF multimers. Whether similar loss of vWF multimers occurs during extracorporeal membrane oxygenation (ECMO) is not clear. METHODS: We conducted a prospective observational study in a clinical cohort of patients who required ECMO for intractable cardiac and/or respiratory failure. The primary end point was the quantity and quality of HMW vWF multimer bands before, during, and after ECMO support. To investigate further changes in primary hemostasis, we also measured vWF antigen activity (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), and factor VIII in 38 patients who required ECMO support before initiation of ECMO (baseline), after 24 and 48 hours on ECMO, and 24 hours after termination of ECMO therapy. RESULTS: Compared with baseline, vWF:Ag and vWF:RCo decreased after 24 hours of ECMO (mean ± SD, vWF:Ag, 307% ± 152% to 261% ± 138%, P = 0.002; vWF:RCo 282% ± 145% to 157% ± 103%, P < 0.0001) and remained lower during ongoing support (vWF:Ag 265% ± 128%, P = 0.025; vWF:RCo 163% ± 94%, P < 0.0001). After termination of ECMO, vWF:Ag was greater than baseline (359% ± 131%, P = 0.004) and vWF:RCo was similar to baseline levels (338% ± 142%, P = 0.046). Compared with baseline, the calculated vWF:RCo/vWF:Ag ratio decreased after 24 hours on support (0.96 ± 0.23 to 0.61 ± 0.17, P ≤ 0.0001) and remained lower during 48 hours on ECMO (0.63 ± 0.18, P ≤ 0.0001). After termination of ECMO support (0.94 ± 0.19, P = 0.437), values rapidly returned to baseline. The number of HMW vWF multimers (n) decreased from baseline after 24 hours on ECMO (21 ± 1.4 to 14 ± 1.8, P ≤ 0.0001) and after 48 hours on ECMO (15 ± 2.1, P ≤ 0.0001). Twenty-four hours after termination of ECMO support, HMW vWF multimeric pattern had returned to baseline values (21 ± 1.8, P = 0.551). CONCLUSIONS: Loss of HMW vWF multimer bands occurred in patients undergoing ECMO support and resolved after the termination of ECMO. Although not detectable with coagulation screening tests, a vWF:RCo/vWF:Ag ratio <0.7 during ECMO was highly indicative for loss of HMW vWF multimers. Our findings may at least in part explain increased bleeding tendency during ECMO therapy. Administration of vWF concentrates may support restoration of primary hemostasis in patients with relevant bleeding during ECMO support.

Intracardiac Doppler Echocardiography for Monitoring of Pulmonary Artery Pressures in High-Risk Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Uncontrolled pulmonary hypertension may cause worse outcomes after transcatheter aortic valve replacement (TAVR), while hemodynamic monitoring is desirable for risk control. Pulmonary artery pressure (PAP) readings obtained by intracardiac Doppler echocardiography were evaluated. METHODS: In 114 patients with symptomatic aortic stenosis and median Society of Thoracic Surgeons scores of 10.5% (interquartile range, 7.7%-15.0%), transfemoral and transapical TAVR was guided by intracardiac Doppler echocardiography. The continuous-wave Doppler beam interrogated the jet of tricuspid regurgitation from the "home view" position. Systolic PAP (PAPs) was estimated as the sum of the pressure gradient derived from the maximum transtricuspid regurgitation jet velocity and the central venous pressure. Mean PAP (PAPm) was calculated by the mean gradient method (1) and the Chemla formula (2). Measurements were obtained immediately before and after TAVR. RESULTS: Pre- and postinterventional readings showed marginal pressure underestimation in comparison with measurements derived from right-heart catheterization: PAPs, -2.7 (95% CI, -3.3 to 2.1) and -1.4 (95% CI, -1.9 to -0.9); PAPm by the mean gradient method, -1.9 (95% CI, -2.2 to -1.6) and -0.1 (95% CI, -0.4 to 0.2). Agreement (95% limits) for PAPs was -8.6 to 3.2 and -6.8 to 4.0; agreement for PAPm by the mean gradient method was -5.4 to 1.6 and -3.4 to 3.2. The repeatability coefficient (95% limits of agreement) for PAPs was excellent: 3.4 (-4.2 to 2.5) and 5.5 (-5.3 to 5.8); repeatability for PAPm was higher by the mean gradient method than by the Chemla method. In ≥ 85% of patients with pulmonary hypertension, PAPm improved after valve deployment. CONCLUSIONS: Intracardiac Doppler echocardiography-derived monitoring of PAP by the mean gradient method is accurate and well applicable to high-risk TAVR candidates for intraprocedural risk control.

Comparison of Anterolateral Minithoracotomy Versus Partial Upper Hemisternotomy in Aortic Valve Replacement.

BACKGROUND: In aortic valve replacement, a comparison between the anterolateral minithoracotomy and the partial upper hemisternotomy approach has not been reported to date. METHODS: From 2006 to 2012, isolated aortic valve replacement was performed in 1,118 consecutive patients. Aortic valve replacement was performed through a anterolateral minithoracotomy in 166 patients (14.9%) and through a partial upper hemisternotomy in 245 patients (21.9%). A propensity score-matched analysis was performed in 160 matched pairs. RESULTS: Conversion to median sternotomy was significantly higher in the anterolateral group (n = 22, 13.1%) than in the hemisternotomy group (n = 7, 4.4%) (p = 0.004). A second cross-clamp was significantly more often necessary in the anterolateral group (n = 14, 8.8%) than in the hemisternotomy group (n =2, 1.3%) (p = 0.003). The median cross-clamp time was significantly longer in the anterolateral group, 93 minutes (range, 43 to 231 minutes) than in the hemisternotomy group, 75 minutes (range, 46 to 137 minutes) (p < 0.0001). The median perfusion time was significantly longer in the anterolateral group, 137 minutes (range, 81 to 456 minutes) than in the hemisternotomy group, 113 minutes (range, 66 to 257 minutes) (p < 0.0001). Significantly more groin adverse events occurred in the anterolateral group (n = 17, 10.8%) than in the hemisternotomy group (n = 0, 0%) (p < 0.0001). No significant difference in 90-day mortality was seen in the anterolateral group (n = 6, 3.8%) than in the hemisternotomy group (n = 2, 1.3%) (p = 0.16). CONCLUSIONS: The anterolateral minithoracotomy is associated with more perioperative adverse events. The partial upper hemisternotomy is an excellent surgical technique for minimally invasive aortic valve replacement in the daily routine for every staff surgeon.

Freestyle root replacement for complex destructive aortic valve endocarditis.

OBJECTIVES: In destructive aortic valve endocarditis with abscess formation in the root, homografts are used more often than xenografts. Because we had reliable perioperative results with Freestyle (Medtronic Inc, Minneapolis, Minn) xenograft root replacement in these complex patients, we analyzed the long-term outcome in this high-risk indication. METHODS: Of 126 consecutive patients with aortic valve endocarditis treated by surgery from 1997 to 2012, 32 (25.4%) received a Freestyle aortic root replacement for severe, destructive valve endocarditis and were studied retrospectively with approval of the local ethical committee. Perioperative complications, recurrence of endocarditis, and long-term morbidity and mortality were analyzed. The follow-up period was 3 months to 11.5 years. RESULTS: Indication for surgery was native (n = 9) and prosthetic valve endocarditis (n = 23). In 18 patients, concomitant procedures were performed: coronary bypass (n = 9), additional valve surgery (n = 6), and ascending aortic surgery (n = 7). Thirty-day mortality was 19.4% (n = 6). There were no instances of technical failure requiring modification of the surgical strategy or reoperation for anastomotic bleeding. Actuarial survival at 5 and 10 years was 61.9% and 54.2%, respectively. Freedom from death, reoperation for prostheses dysfunction, and recurrence of endocarditis as the composite end point at 5 and 10 years was 56.3% and 53.1%, respectively. CONCLUSIONS: The Freestyle root was used successfully with no technical complications in all patients with most severe destructive aortic root endocarditis. In view of this complex patient population, short- and long-term results make this conduit a reliable choice for treatment of this condition.

Relative amplitude index: a new tool for hemodynamic evaluation of periprosthetic regurgitation after transcatheter valve implantation.

OBJECTIVE: The impact of paravalvular aortic regurgitation (PAR) on hemodynamic performance after transcatheter aortic valve implantation (TAVI) remains disputable. Common parameters such as the diastolic blood pressure or the blood pressure amplitude do not provide reproducible results. The aim of our study was to evaluate the impact of PAR on hemodynamics and outcome using the relative amplitude index (RAI). METHODS: PAR was prospectively evaluated by echocardiography before discharge in 110 patients. The RAI was calculated according to the formula: RAI = [(Post-TAVI BP amplitude)/(Post-TAVI SBP) - (Pre-TAVI BP amplitude)/(Pre-TAVI SBP)] × 100%, where BP is blood pressure and SBP is systolic blood pressure. Correlations of increased RAI with perioperative outcome were investigated and factors influencing mortality were isolated. RESULTS: The incidence of moderate and severe PAR after TAVI was 9% and 1%, respectively. Diastolic pressure or post-TAVI amplitude did not correlate to perioperative outcome. RAI increased from 2 when PAR was <2+ to 7 when PAR was ≥2+ (P = .006). A cut-off value of RAI ≥14 was associated with increased perioperative mortality (29 vs 5%; P = .013) and acute renal injury requiring dialysis (71 vs 18%; P = .001). RAI ≥14 was also associated with higher follow-up mortality at 1 year (57 vs 16%; P = .007). RAI ≥14 (odds ratio [OR], 3.390; 95% confidence interval [CI], 1.6-7.194; P = .00146), PAR ≥2+ (OR, 4.717; 95% CI, 1.828-12.195; P = .00135), and perioperative renal replacement therapy (OR, 12.820; 95% CI, 5.181-31.250; P = .00031) were found to be independent predictors of mortality at 1 year. CONCLUSIONS: The RAI is a useful tool to predict perioperative and 1-year outcome in patients with PAR after TAVI.

Benefits of high-pitch 128-slice dual-source computed tomography for planning of transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has emerged as an alternative treatment for high-risk and inoperable patients. Advanced multimodality imaging, including computed tomography (CT), plays a key role for optimized planning of TAVI. METHODS: Forty-nine patients (25 women; age, 82.3±8.8 year) with severe aortic stenosis scheduled for TAVI were examined with 128-slice high-pitch dual-source prospective aortoiliac CT angiography (CTA). The 3-coronary-sinus-alignment (3-CSA) plane, comprising left and right anterior oblique and craniocaudal projection, was defined from three-dimensional volume-rendered technique data sets and compared with the intraoperative angiographic plane (deployment plane) used for device implantation. A tolerance level of ±5-degree deviation was acceptable. Volume of intraoperative iodine contrast agent was compared before and after the implementation of the 3-CSA plane estimation by CT. RESULTS: All 49 patients underwent TAVI, during which 6 CoreValves (Medtronic, Minneapolis, MN) and 43 Sapien valves (Edwards Lifesciences, Irvine, CA) were successfully implanted using transapical (n=29), transfemoral (n=17), and transaxillary access (n=4). No severe complications occurred. In 47 patients (96%), CTA correctly predicted the 3-CSA plane used for device implantation. Mean left anterior oblique by CTA was 5.3±6.5 degrees and craniocaudal was -1.3±10.1 degrees. Mean left anterior oblique deviation between CTA and the intraoperative projection was 2.1±2.7 degrees and craniocaudal was 1.7±3.0 degrees. Ostium heights of the right and left coronary arteries were 12±1.9 and 12.9±3.3 mm. No over-stenting occurred in left coronary artery ostia of 8 mm or more. Contrast volume was reduced from 81.8±25.6 to 59.4±40.2 mL (p=0.05) when using 3-CSA plane estimation by CT for final prosthesis implantation plane. CONCLUSIONS: Aortoiliac high-pitch 128-slice dual-source CT contributes to TAVI planning, including reliable prediction of the 3-CSA valve deployment plane, which saves contrast volume during the procedure and may facilitate correct valve placement.