Assessment of histological characteristics, imaging markers, and rt-PA susceptibility of ex vivo venous thrombi.

Venous thromboembolism is a significant source of morbidity and mortality worldwide. Catheter-directed thrombolytics is the primary treatment used to relieve critical obstructions, though its efficacy varies based on the thrombus composition. Non-responsive portions of the specimen often remain in situ, which prohibits mechanistic investigation of lytic resistance or the development of diagnostic indicators for treatment outcomes. In this study, thrombus samples extracted from venous thromboembolism patients were analyzed ex vivo to determine their histological properties, susceptibility to lytic therapy, and imaging characteristics. A wide range of thrombus morphologies were observed, with a dependence on age and etymology of the specimen. Fibrinolytic inhibitors including PAI-1, alpha 2-antiplasmin, and TAFI were present in samples, which may contribute to the response venous thrombi to catheter-directed thrombolytics. Finally, a weak but significant correlation was observed between the response of the sample to lytic drug and its magnetic microstructure assessed with a quantitative MRI sequence. These findings highlight the myriad of changes in venous thrombi that may promote lytic resistance, and imaging metrics that correlate with treatment outcomes.

In vitro assessment of stiffness-dependent histotripsy bubble cloud activity in gel phantoms and blood clots.

As a bubble-based ablative therapy, the efficacy of histotripsy has been demonstrated in healthy or acutely diseased models. Chronic conditions associated with stiff tissues may require additional bubble activity prior to histotripsy liquefaction. In this study, histotripsy pulses were generated in agarose phantoms of Young's moduli ranging from 12.3 to 142 kPa, and in vitro clot models with mild and strong platelet-activated retraction. Bubble cloud emissions were tracked with passive cavitation imaging, and the threshold acoustic power associated with phantom liquefaction was extracted with receiver operator characteristic analysis. The power of histotripsy-generated emissions and the degree of liquefaction were tabulated for both clot models. For the agarose phantoms, the acoustic power associated with liquefaction increased with Young's modulus. When grouped based on agarose concentration, only two arms displayed a significant difference in the liquefaction threshold acoustic power (22.1 kPa versus 142 kPa Young's modulus). The bubble cloud dynamics tracked with passive cavitation imaging indicated no strong changes in the bubble dynamics based on the phantom stiffness. For identical histotripsy exposure, the power of acoustic emissions and degree of clot lysis did not vary based on the clot model. Overall, these results indicate that a fixed threshold acoustic power mapped with passive cavitation imaging can be utilized for predicting histotripsy liquefaction over a wide range of tissue stiffness.

Cost-utility of extracorporeal cardiopulmonary resuscitation in patients with cardiac arrest.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) is a resource-intensive tool that provides haemodynamic and respiratory support in patients who have suffered cardiac arrest. In this study, we investigated the cost-utility of ECPR (cost/QALY) in cardiac arrest patients treated at our institution. METHODS: We performed a retrospective review of patients who received ECPR following cardiac arrest between 2012 and 2018. All medical care-associated charges with ECPR and subsequent hospital admission were recorded. The quality-of-life of survivors was assessed with the Health Utilities Index Mark II. The cost-utility of ECPR was calculated with cost and quality-of-life data. RESULTS: ECPR was used in 32 patients (15/32 in-hospital, 47%) with a median age of 55.0 years (IQR 46.3-63.3 years), 59% male and 66% African American. The median duration of ECPR support was 2.1 days (IQR 0.9-3.8 days). Survival to hospital discharge was 16%. The median score of the Health Utilities Index Mark II at discharge for the survivors was 0.44 (IQR 0.32-0.52). The median operating cost for patients undergoing ECMO was $125,683 per patient (IQR $49,751-$206,341 per patient). The calculated cost-utility for ECPR was $56,156/QALY gained. CONCLUSIONS: The calculated cost-utility is within the threshold considered cost-effective in the United States (<$150,000/QALY gained). These results are comparable to the cost-effectiveness of heart transplantation for end-stage heart failure. Larger studies are needed to assess the cost-utility of ECPR and to identify whether other factors, such as patient characteristics, affect the cost-utility benefit.

Sequential Organ Failure Assessment Score at Presentation Predicts Survival in Patients Treated With Percutaneous Veno-Arterial Extracorporeal Membrane Oxygenation.

BACKGROUND AND PURPOSE: This study sought to investigate demographic, clinical, and procedural determinants of outcomes in patients treated with percutaneous veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) initiated in the cardiac catheterization laboratory with a portable system. METHODS: We performed a retrospective review of patients treated with percutaneous VA-ECMO during the study period at our institution. A logistic regression model was applied to investigate the association between sequential organ failure assessment (SOFA) score and survivor status. Fisher's exact test was used to examine the association between survivor status and cannula size (15 Fr vs >15 Fr). RESULTS: Percutaneous VA-ECMO was initiated in 25 patients. At 30 days, 10 patients were alive (40%). Fifteen patients had cardiac arrest (CA) prior to ECMO initiation, of which 5 were alive at 30 days (33%). Survivors had a lower baseline median SOFA score (9 vs 16; P=.02; odds ratio, 0.577). Use of a smaller cannula was associated with survival (P=.01). There was an association between the size of the arterial cannula and increased blood transfusions (P<.01). CONCLUSIONS: Lower presenting SOFA score and smaller cannula size were associated with increased survival in patients with cardiogenic shock (CS) or CA who underwent percutaneous VA-ECMO placed in the cardiac catheterization laboratory using a portable system. Calculation of the SOFA score at presentation may help physicians determine which patients may derive benefit from ECMO. Smaller cannula size, while decreasing the amount of flow, may result in decreased bleeding and increased survival.

Clinical and economic effectiveness of percutaneous ventricular assist devices for high-risk patients undergoing percutaneous coronary intervention.

BACKGROUND: Comparative effectiveness research (CER) is taking a more prominent role in formalizing hospital treatment protocols and health-care coverage policies by having health-care providers consider the impact of new devices on costs and outcomes. CER balances the need for innovation with fiscal responsibility and evidence-based care. This study compared the clinical and economic impact of percutaneous ventricular assist devices (pVAD) with intraaortic balloon pumps for high-risk patients undergoing percutaneous coronary intervention (PCI). METHODS: This study conducted a review of all comparative randomized control trials of the pVADS (Impella and TandemHeart) vs IABP for patients undergoing high-risk percutaneous coronary intervention (PCI). A retrospective analysis of the 2010 and 2011 Medicare MEDPAR data files was also performed to compare procedural costs and hospital length of stay (LOS). Readmission rates between the devices were also studied. RESULTS: Based on available trials, there is no significant clinical benefit with pVAD compared to IABP. Use of pVADs is associated with increased length of Intensive Care Unit stay and a total longer LOS. The incremental budget impact for pVADs was $33,957,839 for the United States hospital system (2010-2011). CONCLUSIONS: pVADs are not associated with improved clinical outcomes, reduced hospital length of stay, or reduced readmission rates. Management of high-risk PCI and cardiogenic shock patients with IABP is more cost effective than a routine use of pVADS. Use of IABP as initial therapy in high-risk PCI and cardiogenic shock patients may result in savings of up to $2.5 billion annually of incremental costs to the hospital system.

Overview of Technical and Cost Considerations in Complex Percutaneous Coronary Intervention.

Complex percutaneous coronary intervention (PCI), encompassing an ever-expanding range of challenging lesion sets and patient populations, accounts for a significant proportion of PCI procedures being performed currently. Specific lesion types associated with lower rates of procedural success and higher rates of recurrence or major adverse cardiac events (MACE) include multivessel disease, unprotected left main coronary artery disease, fibrocalcific or undilatable lesions, chronic total occlusions, degenerated saphenous vein graft lesions, thrombotic lesions, and bifurcation disease. Validated tools and technical strategies currently exist to address most procedural scenarios encountered and should be familiar to the complex PCI operator. Anticipated clinical outcomes, projected resource utilization, and cost considerations should all factor into the decisions of when, how, and in whom to intervene.