Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used to treat cardiogenic shock. However, VA-ECMO might hamper myocardial recovery. The Impella unloads the left ventricle. The aim of this study was to evaluate if left ventricular unloading in cardiogenic shock patients treated with VA-ECMO was associated with lower mortality. Methods: Data from 686 consecutive patients with cardiogenic shock treated with VA-ECMO with or without left ventricular unloading (using an Impella) at 16 tertiary-care centers in 4 countries were collected. The association between left ventricular unloading and 30-day mortality was assessed by Cox regression models in a 1:1 propensity-score-matched cohort. Results: Left ventricular unloading was used in 337 of the 686 patients (49%). After matching, 255 patients with left ventricular unloading were compared with 255 patients without left ventricular unloading. In the matched cohort, left ventricular unloading was associated with lower 30-day mortality (hazard ratio 0.79, 95% confidence interval 0.63-0.98, p=0.03) without differences in various subgroups. Complications occurred more frequently in patients with left ventricular unloading; e.g. severe bleeding in 98 (38.4%) vs. 45 (17.9%), access-site related ischemia in 55 (21.6%) vs. 31 (12.3%), abdominal compartment in 23 (9.4%) vs. 9 (3.7%) and renal replacement therapy in 148 (58.5%) vs. 99 (39.1%). Conclusions: In this international, multicenter cohort study, left ventricular unloading was associated with lower mortality in cardiogenic shock patients treated with VA-ECMO, despite higher complication rates. These findings support use of left ventricular unloading in cardiogenic shock patients treated with VA-ECMO and call for further validation, ideally in a randomized, controlled trial.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been used for refractory cardiogenic shock; however, it is associated with increased left ventricular afterload. Outcomes associated with the combination of a percutaneous left ventricular assist device (Impella) and VA-ECMO remains largely unknown. We retrospectively reviewed patients treated for refractory cardiogenic shock with VA-ECMO (2014-2016). The primary outcome was all-cause mortality within 30 days of VA-ECMO implantation. Secondary outcomes included duration of support, stroke, major bleeding, hemolysis, inotropic score, and cardiac recovery. Outcomes were compared between the VA-ECMO cohort and VA-ECMO + Impella (ECPELLA cohort). Sixty-six patients were identified: 30 ECPELLA and 36 VA-ECMO. Fifty-eight percentage of VA-ECMO patients (n = 21) had surgical venting, as compared with 100% of the ECPELLA cohort (n = 30) which had Impella (±surgical vent). Both cohorts demonstrated relatively similar baseline characteristics except for higher incidence of ST-elevation myocardial infarction (STEMI) and percutaneous coronary intervention (PCI) in the ECPELLA cohort. Thirty-day all-cause mortality was significantly lower in the ECPELLA cohort (57% vs. 78%; hazard ratio [HR] 0.51 [0.28-0.94], log rank p = 0.02), and this difference remained intact after correcting for STEMI and PCI. No difference between secondary outcomes was observed, except for the inotrope score which was greater in VA-ECMO group by day 2 (11 vs. 0; p = 0.001). In the largest US-based retrospective study, the addition of Impella to VA-ECMO for patients with refractory cardiogenic shock was associated with lower all-cause 30 day mortality, lower inotrope use, and comparable safety profiles as compared with VA-ECMO alone.

Purpose To retrospectively validate a first-pass analysis (FPA) technique that combines computed tomographic (CT) angiography and dynamic CT perfusion measurement into one low-dose examination. Materials and Methods The study was approved by the animal care committee. The FPA technique was retrospectively validated in six swine (mean weight, 37.3 kg ± 7.5 [standard deviation]) between April 2015 and October 2016. Four to five intermediate-severity stenoses were generated in the left anterior descending artery (LAD), and 20 contrast material-enhanced volume scans were acquired per stenosis. All volume scans were used for maximum slope model (MSM) perfusion measurement, but only two volume scans were used for FPA perfusion measurement. Perfusion measurements in the LAD, left circumflex artery (LCx), right coronary artery, and all three coronary arteries combined were compared with microsphere perfusion measurements by using regression, root-mean-square error, root-mean-square deviation, Lin concordance correlation, and diagnostic outcomes analysis. The CT dose index and size-specific dose estimate per two-volume FPA perfusion measurement were also determined. Results FPA and MSM perfusion measurements (P and P) in all three coronary arteries combined were related to reference standard microsphere perfusion measurements (P), as follows: P = 1.02 P + 0.11 (r = 0.96) and P = 0.28 P + 0.23 (r = 0.89). The CT dose index and size-specific dose estimate per two-volume FPA perfusion measurement were 10.8 and 17.8 mGy, respectively. Conclusion The FPA technique was retrospectively validated in a swine model and has the potential to be used for accurate, low-dose vessel-specific morphologic and physiologic assessment of coronary artery disease. RSNA, 2017.

Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques.

Background Computerized tomography (CT) angiography is an important tool for evaluation of coronary artery disease (CAD), but often correlates poorly with myocardial ischemia. Current dynamic CT perfusion techniques can assess ischemia, but have limited accuracy and deliver high radiation dose. Therefore, an accurate, low-dose, dynamic CT perfusion technique is needed. Methods and Results A total of 20 contrast enhanced CT volume scans were acquired in 5 swine (40 ± 10 kg) to generate CT angiography and perfusion images. Varying degrees of stenosis were induced using a balloon catheter in the proximal left anterior descending (LAD) coronary artery and a pressure wire was used for reference fractional flow reserve (FFR) measurement. Perfusion measurements were made with only two volume scans using a new first-pass analysis (FPA) technique and with 20 volume scans using an existing maximum slope model (MSM) technique. Perfusion (P) and FFR measurements were related by PFPA = 1.01 FFR − 0.03 (R2 = 0.85) and PMSM = 1.03 FFR − 0.03 (R2 = 0.80) for FPA and MSM techniques, respectively. Additionally, the effective radiation doses were calculated to be 2.64 and 26.4 mSv for FPA and MSM techniques, respectively. Conclusions A new FPA-based dynamic CT perfusion technique was validated in a swine animal model. The results indicate that the FPA technique can potentially be used for improved anatomical and functional assessment of CAD at a relatively low radiation dose.