A Narrative Review of Revascularization in Chronic Coronary Syndrome/Disease: Concepts and Misconceptions.

Ischemic heart disease represents a significant global burden of morbidity and mortality. While revascularization strategies are well defined in acute settings, there are uncertainties regarding chronic coronary artery disease treatment. Recent trials have raised doubts about the necessity of revascularization for "stable", chronic coronary syndromes or disease, leading to a shift towards a more conservative approach. However, the issue remains far from settled. In this narrative review, we offer a summary of the most pertinent evidence regarding revascularization for chronic coronary disease, while reflecting on less-often-discussed details of major clinical trials. The cumulative evidence available indicates that there can be a prognostic benefit from revascularization in chronic coronary syndrome patients, provided there is significant ischemia, as demonstrated by either imaging or coronary physiology. Trials that have effectively met this criterion consistently demonstrate a reduction in rates of spontaneous myocardial infarction, which holds both prognostic and clinical significance. The prognostic benefit of revascularization in patients with heart failure with reduced ejection fraction remains especially problematic, with a single contemporary trial favouring surgical revascularization. The very recent publication of a trial focused on revascularizing non-flow-limiting "vulnerable" plaques adds further complexity to the field. The ongoing debates surrounding revascularization in chronic coronary syndromes emphasize the importance of personalized strategies. Revascularization, added to the foundational pillar of medical therapy, should be considered, taking into account symptoms, patient preferences, coronary anatomy and physiology, ischemia tests and intra-coronary imaging.

Coronary Intravascular Lithotripsy Effectiveness and Safety in a Real-World Cohort.

Background: Coronary artery calcification is a predictor of adverse outcomes after percutaneous coronary intervention (PCI). Intravascular lithotripsy (IVL) is a promising tool for the treatment of calcified lesions. The aim of this study was to assess the effectiveness and safety of IVL. Methods: A single-center observational study of PCI procedure, with assessment of the outcomes of patients undergoing PCI using IVL, was performed. Angiographic procedural success was used as the primary effectiveness endpoint. The primary safety endpoint was defined as a composite of cardiac death, myocardial infarction and target vessel revascularization within 30 days. Results: A total of 111 patients were included. Indications for PCI spanned the spectrum of chronic (53.2%) and acute coronary syndromes (43%). Lesion preparation before IVL was performed with non-compliant (42%), cutting or OPN (14.4%) balloons and with atherectomy techniques in 11% of procedures. Intravascular imaging was used in 21.6% of procedures. The primary effectiveness endpoint was achieved in 100% and the primary safety endpoint in 3.6% of procedures. Peri-procedural complications were minimal and successfully resolved. Conclusions: IVL was an effective and safe technique for the treatment of calcified coronary lesions. These findings contribute to the growing body of evidence supporting the use of IVL in the management of these challenging scenarios.

Coronary physiology instantaneous wave-free ratio (iFR) derived from x-ray angiography using artificial intelligence deep learning models: a pilot study.

OBJECTIVES: Coronary angiography (CAG)-derived physiology methods have been developed in an attempt to simplify and increase the usage of coronary physiology, based mostly on dynamic fluid computational algorithms. We aimed to develop a different approach based on artificial intelligence methods, which has seldom been explored. METHODS: Consecutive patients undergoing invasive instantaneous free-wave ratio (iFR) measurements were included. We developed artificial intelligence (AI) models capable of classifying target lesions as positive (iFR ≤ 0.89) or negative (iFR > 0.89). The predictions were then compared to the true measurements. RESULTS: Two hundred-fifty measurements were included, and 3 models were developed. Model 3 had the best overall performance: accuracy, negative predictive value (NPV), positive predictive value (PPV), sensitivity, and specificity were 69%, 88%, 44%, 74%, and 67%, respectively. Performance differed per target vessel. For the left anterior descending artery (LAD), model 3 had the highest accuracy (66%), while model 2 the highest NPV (86%) and sensitivity (91%). PPV was always low/modest. Model 1 had the highest specificity (68%). For the right coronary artery, model 1's accuracy was 86%, NPV was 97%, and specificity was 87%, but all models had low PPV (maximum 25%) and low/modest sensitivity (maximum 60%). For the circumflex, model 1 performed best: accuracy, NPV, PPV, sensitivity, and specificity were 69%, 96%, 24%, 80%, and 68%, respectively. CONCLUSIONS: We developed 3 AI models capable of binary iFR estimation from CAG images. Despite modest accuracy, the consistently high NPV is of potential clinical significance, as it would enable avoiding further invasive maneuvers after CAG. This pivotal study offers proof of concept for further development.

Interventional cardiology in cancer patients: A position paper from the Portuguese Cardiovascular Intervention Association and the Portuguese Cardio-Oncology Study Group of the Portuguese Society of Cardiology.

The field of Cardio-Oncology has grown significantly, especially during the last decade. While awareness of cardiotoxicity due to cancer disease and/or therapies has greatly increased, much of the attention has focused on myocardial systolic disfunction and heart failure. However, coronary and structural heart disease are also a common issue in cancer patients and encompass the full spectrum of cardiotoxicity. While invasive percutaneous or surgical intervention, either is often needed or considered in cancer patients, limited evidence or guidelines are available for dealing with coronary or structural heart disease. The Society for Cardiovascular Angiography and Interventions consensus document published in 2016 is the most comprehensive document regarding this particular issue, but relevant evidence has emerged since, which render some of its considerations outdated. In addition to that, the recent 2022 ESC Guidelines on Cardio-Oncology only briefly discuss this topic. As a result, the Portuguese Association of Cardiovascular Intervention and the Cardio-Oncology Study Group of the Portuguese Society of Cardiology have partnered to produce a position paper to address the issue of cardiac intervention in cancer patients, focusing on percutaneous techniques. A brief review of available evidence is provided, followed by practical considerations. These are based both on the literature as well as accumulated experience with these types of patients, as the authors are either interventional cardiologists, cardiologists with experience in the field of Cardio-Oncology, or both.

Segmentation of X-ray coronary angiography with an artificial intelligence deep learning model: Impact in operator visual assessment of coronary stenosis severity.

BACKGROUND: Visual assessment of the percentage diameter stenosis (%DSVE ) of lesions is essential in coronary angiography (CAG) interpretation. We have previously developed an artificial intelligence (AI) model capable of accurate CAG segmentation. We aim to compare operators' %DSVE in angiography versus AI-segmented images. METHODS: Quantitative coronary analysis (QCA) %DS (%DSQCA ) was previously performed in our published validation dataset. Operators were asked to estimate %DSVE of lesions in angiography versus AI-segmented images in separate sessions and differences were assessed using angiography %DSQCA as reference. RESULTS: A total of 123 lesions were included. %DSVE was significantly higher in both the angiography (77% ± 20% vs. 56% ± 13%, p < 0.001) and segmentation groups (59% ± 20% vs. 56% ± 13%, p < 0.001), with a much smaller absolute %DS difference in the latter. For lesions with %DSQCA of 50%-70% (60% ± 5%), an even higher discrepancy was found (angiography: 83% ± 13% vs. 60% ± 5%, p < 0.001; segmentation: 63% ± 15% vs. 60% ± 5%, p < 0.001). Similar, less pronounced, findings were observed for %DSQCA < 50% lesions, but not %DSQCA > 70% lesions. Agreement between %DSQCA /%DSVE across %DSQCA strata (<50%, 50%-70%, >70%) was approximately twice in the segmentation group (60.4% vs. 30.1%; p < 0.001). %DSVE inter-operator differences were smaller with segmentation. CONCLUSION: %DSVE was much less discrepant with segmentation versus angiography. Overestimation of %DSQCA < 70% lesions with angiography was especially common. Segmentation may reduce %DSVE overestimation and thus unwarranted revascularization.

Coronary X-ray angiography segmentation using Artificial Intelligence: a multicentric validation study of a deep learning model.

INTRODUCTION: We previously developed an artificial intelligence (AI) model for automatic coronary angiography (CAG) segmentation, using deep learning. To validate this approach, the model was applied to a new dataset and results are reported. METHODS: Retrospective selection of patients undergoing CAG and percutaneous coronary intervention or invasive physiology assessment over a one month period from four centers. A single frame was selected from images containing a lesion with a 50-99% stenosis (visual estimation). Automatic Quantitative Coronary Analysis (QCA) was performed with a validated software. Images were then segmented by the AI model. Lesion diameters, area overlap [based on true positive (TP) and true negative (TN) pixels] and a global segmentation score (GSS - 0 -100 points) - previously developed and published - were measured. RESULTS: 123 regions of interest from 117 images across 90 patients were included. There were no significant differences between lesion diameter, percentage diameter stenosis and distal border diameter between the original/segmented images. There was a statistically significant albeit minor difference [0,19 mm (0,09-0,28)] regarding proximal border diameter. Overlap accuracy ((TP + TN)/(TP + TN + FP + FN)), sensitivity (TP / (TP + FN)) and Dice Score (2TP / (2TP + FN + FP)) between original/segmented images was 99,9%, 95,1% and 94,8%, respectively. The GSS was 92 (87-96), similar to the previously obtained value in the training dataset. CONCLUSION: the AI model was capable of accurate CAG segmentation across multiple performance metrics, when applied to a multicentric validation dataset. This paves the way for future research on its clinical uses.

Artificial intelligence-based diagnosis of acute pulmonary embolism: Development of a machine learning model using 12-lead electrocardiogram.

INTRODUCTION: Pulmonary embolism (PE) is a life-threatening condition, in which diagnostic uncertainty remains high given the lack of specificity in clinical presentation. It requires confirmation by computed tomography pulmonary angiography (CTPA). Electrocardiography (ECG) signals can be detected by artificial intelligence (AI) with precision. The purpose of this study was to develop an AI model for predicting PE using a 12-lead ECG. METHODS: We extracted 1014 ECGs from patients admitted to the emergency department who underwent CTPA due to suspected PE: 911 ECGs were used for development of the AI model and 103 ECGs for validation. An AI algorithm based on an ensemble neural network was developed. The performance of the AI model was compared against the guideline recommended clinical prediction rules for PE (Wells and Geneva scores combined with a standard D-dimer cut-off of 500 ng/mL and an age-adjusted cut-off, PEGeD and YEARS algorithm). RESULTS: The AI model achieves greater specificity to detect PE than the commonly used clinical prediction rules. The AI model shown a specificity of 100% (95% confidence interval (CI): 94-100) and a sensitivity of 50% (95% CI: 33-67). The AI model performed significantly better than the other models (area under the curve 0.75; 95% CI 0.66-0.82; p<0.001), which had nearly no discriminative power. The incidence of typical PE ECG features was similar in patients with and without PE. CONCLUSION: We developed and validated a deep learning-based AI model for PE diagnosis using a 12-lead ECG and it demonstrated high specificity.

Development of deep learning segmentation models for coronary X-ray angiography: Quality assessment by a new global segmentation score and comparison with human performance.

INTRODUCTION AND OBJECTIVES: Although automatic artificial intelligence (AI) coronary angiography (CAG) segmentation is arguably the first step toward future clinical application, it is underexplored. We aimed to (1) develop AI models for CAG segmentation and (2) assess the results using similarity scores and a set of criteria defined by expert physicians. METHODS: Patients undergoing CAG were randomly selected in a retrospective study at a single center. Per incidence, an ideal frame was segmented, forming a baseline human dataset (BH), used for training a baseline AI model (BAI). Enhanced human segmentation (EH) was created by combining the best of both. An enhanced AI model (EAI) was trained using the EH. Results were assessed by experts using 11 weighted criteria, combined into a Global Segmentation Score (GSS: 0-100 points). Generalized Dice Score (GDS) and Dice Similarity Coefficient (DSC) were also used for AI models assessment. RESULTS: 1664 processed images were generated. GSS for BH, EH, BAI and EAI were 96.9+/-5.7; 98.9+/-3.1; 86.1+/-10.1 and 90+/-7.6, respectively (95% confidence interval, p<0.001 for both paired and global differences). The GDS for the BAI and EAI was 0.9234±0.0361 and 0.9348±0.0284, respectively. The DSC for the coronary tree was 0.8904±0.0464 and 0.9134±0.0410 for the BAI and EAI, respectively. The EAI outperformed the BAI in all coronary segmentation tasks, but performed less well in some catheter segmentation tasks. CONCLUSIONS: We successfully developed AI models capable of CAG segmentation, with good performance as assessed by all scores.

Clinical experience of a cardio-oncology consultation at a tertiary university hospital in Portugal: An observational study.

INTRODUCTION: Heart disease and cancer are the two leading causes of morbidity and mortality worldwide. Advances in cancer screening and management have led to longer survival and better quality of life. Despite this progress, many cancer patients experience cardiovascular complications during and after cancer treatment. This study describes the experience of a cardio-oncology program at tertiary academic hospital. METHODS: In this retrospective observational study, cancer patients referred to the CHULN cardio-oncology consultation (COC) between January 2016 and December of 2019 were included. Data collected included: patient demographics, cancer type, reason for referral, cardiovascular risk factors, cardiac and oncologic treatments and clinical outcomes. RESULTS: A total of 520 patients (mean age: 65 ± 14 years; 65% women) were referred to the COC. The main reasons for referral were suspected heart failure (26%), pre-high risk chemotherapy assessment (20%) and decreased LVEF (15%). Pre-existing cardiovascular risk factors were common (79%) and 309 (59%) were taking cardiac medications. The most common type of malignancy was breast cancer (216, 41%) followed by gastrointestinal (139, 27%). More than half received anthracycline-based regimens (303, 58%). Most patients (401; 77%) successfully completed cancer therapy. At the time of last data collection, the majority of patients were alive (430, 83%). Cardiac-related mortality was observed in 16%. CONCLUSIONS: The close collaboration between cardiology and oncology teams and timely cardiac monitoring was the key to the majority of patients to completing their prescribed cancer therapy.

The CTo-aBCDE score: A new predictor of success in chronic total occlusions.

INTRODUCTION: Patient selection for percutaneous coronary intervention (PCI) in chronic total occlusions (CTOs) is crucial to procedural success. Our aim was to identify independent predictors of success in CTO PCI in order to create an accurate score. METHODS: In a single-center observational registry of CTO PCI, demographic and clinical data and anatomical characteristics of coronary lesions were recorded. Linear and logistic regression analysis were used to identify predictors of success. A score to predict success was created and its accuracy was measured by receiver operating curve analysis. RESULTS: A total of 377 interventions were performed (334 patients, age 68±11 years, 75% male). The success rate was 65% per patient and 60% per procedure. Predictors of success in univariate analysis were absence of active smoking (OR 2.02, 95% CI 1.243-3.29; p=0.005), presence of tapered stump (OR 5.2, 95% CI 2.7-10.2; p<0.001), absence of tortuosity (OR 6.44; 95% CI 3.02-13.75; p<0.001), absence of bifurcation (OR 1.95; 95% CI 1.08-3.51; p=0.026), absence of calcification (OR 3.1; 95% CI 3.10-5.41; p<0.001), LAD as target vessel (OR 1.9, 95% CI 1.0-3.5; p=0.048), and CTO length <20 mm (OR 3.00, 95% CI 1.69-5.3; p<0.001). Only anatomical factors were independent predictors of success, and an anatomical score (0-11 points) with high accuracy (area under the curve 0.831) was subsequently created. A score <3 was associated with low probability of success (15%), 3-8 with intermediate probability (55%), and >8 with high probability (95%). CONCLUSION: In our sample only anatomical characteristics were predictors of success. The creation of a score to predict success, with good accuracy, may enable selection of cases that can be treated by any operator, those in which a dedicated operator will be desirable, and those with an extremely low probability of success, which should be considered individually for conservative management, surgical revascularization or PCI by a team experienced in CTO.

Transradial left ventricular endomyocardial biopsy feasibility, safety and clinical usefulness: Initial experience of a tertiary university center.

INTRODUCTION AND OBJECTIVES: Over the last decade, several studies have suggested that left ventricular endomyocardial biopsy is safer and has a higher diagnostic yield than transvenous right ventricular biopsy. In addition, recent publications indicate that the transradial approach is a feasible and safe alternative to the transfemoral approach for sampling the left ventricle. We report our initial experience with transradial endomyocardial biopsy with regards to feasibility, safety and usefulness. METHODS: Single-center registry of consecutive patients undergoing intended transradial left endomyocardial biopsy. Clinical and technical data were collected prospectively, with a particular focus on success rate and complications. RESULTS: Twenty-seven patients were screened for left ventricle biopsy. Twenty (25) were selected for an intended transradial approach (mean age 51±18 years old, 22 male). Success rate was 100% with no crossover to femoral approach. There were no major complications. Two patients experienced mild radial spasm. One of them also had a run of non-sustained ventricular tachycardia. Indication for biopsy was either myocarditis or cardiomyopathy of unknown etiology. The final diagnosis was acute lymphocytic myocarditis in five patients, chronic myocarditis in one patient, amyloid light-chain amyloidosis in four patients and transthyretin amyloidosis in six patients. Myocarditis was ruled out in eight patients and amyloidosis in one patient. CONCLUSIONS: Transradial left ventricle endomyocardial biopsy is a very safe and feasible method of sampling the myocardium for histopathological analysis, with a good diagnostic yield and clinically meaningful results in properly selected patients.

Transradial Approach for Left Ventricular Endomyocardial Biopsy.

BACKGROUND: Left ventricular endomyocardial biopsy (LV-EMB) may offer a superior diagnostic yield compared with right ventricular endomyocardial biopsy (RV-EMB) in conditions predominantly affecting the LV but is underused compared with RV-EMB. Despite the steep uptake of radial approach in coronary interventions, LV-EMB is usually performed via the femoral artery in contemporary practice. Therefore, the aim of this study was to assess the safety and feasibility of LV-EMB via a transradial approach in a multicentre registry. METHODS: One-hundred and two patients who underwent LV-EMB via transradial approach were included. Clinical characteristics, procedural, safety and feasibility data were evaluated. RESULTS: LV-EMB was successfully performed via transradial access in 101 (99%) patients. Mild or moderate radial artery spasm occurred in 12 (12%) patients, but only 1 (0.98%) patient required conversion to femoral access due to severe spasm. A total of 80 (78%) patients had LV-EMB via a sheathless guide catheter. Among those, 77 (96.3%) patients had 7.5-French sheathless guides, and 3 (3.8%) patients had 8.5-French sheathless guides inserted. Radial sheaths were used in the remaining 22 patients, with 5-French sheaths in 21 of 22 patients. Heparin was administered to 93.1% of patients at a median dose of 5000 (3000-5000) IU. The remaining patients followed a provisional strategy upon patent hemostasis achievement. No access site-related complications were reported. There were no major complications (pericardial tamponade, life-threatening arrhythmia, cerebrovascular accident or death). CONCLUSIONS: In a population of patients undergoing transradial LV-EMB, the procedural success rate was high and showed an excellent safety profile. Further studies comparing transradial and transfemoral routes may help expand the use of transradial access for LV-EMB.

Comparative analysis of fractional flow reserve and instantaneous wave-free ratio: Results of a five-year registry. / Análise comparativa do fractional flow reserve (FFR) e do instantaneous wave­free ratio (iFR): resultados de um registo de 5 anos.

INTRODUCTION AND OBJECTIVE: Assessment of coronary lesions by the instantaneous wave free ratio (iFR) has generated significant debate. We aimed to assess the diagnostic performance of iFR and its impact on the decision to use fractional flow reserve (FFR) and on procedural characteristics. METHODS: In this single-center registry of patients undergoing functional assessment of coronary lesions, FFR was used as a reference for assessing the diagnostic performance of iFR. An iFR value <0.86 was considered positive and a value >0.93 was considered negative. RESULTS: Functional testing was undertaken of 402 lesions, of which 154 were assessed with both techniques, 222 with FFR only, and 26 with iFR only. Using a cut-off of ≤0.80 for iFR, the area under the curve was 0.73 (95% CI 0.65-0.81), with an optimal value of ≤0.91. FFR was undertaken in 93 out of 94 lesions with an inconclusive iFR and was performed in 69.1% of the remaining iFR-tested lesions. Concordance between iFR and FFR was 87% (chi-square=22.43; p<0.001). Notwithstanding, there were four out of 13 cases (30.7%) of positive iFR with negative FFR and three out of 42 (7.1%) cases of negative iFR and positive FFR. This difference was significant (p=0.026). iFR had no impact on procedure time, fluoroscopy time or radiation dose. CONCLUSION: iFR had a reasonable diagnostic performance. Operators often chose to perform FFR despite conclusive iFR results. iFR and FFR were highly concordant, but a non-negligible proportion of lesions classified as ischemic by iFR were classified as non-ischemic by FFR. iFR had no impact on procedural characteristics.

Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation: follow-up results from a prospective observational study.

Aims: Cardiac Resynchronization Therapy (CRT) is associated with a particularly high non-response rate in patients with atrial fibrillation (AF). We aimed to assess the effectiveness of triple-site (Tri-V) pacing CRT in this population. Methods and results: Prospective observational study of patients with permanent AF who underwent CRT implantation with an additional right ventricle lead in the outflow tract septal wall. After implantation, programming mode (Tri-V or biventricular pacing) was selected based on cardiac output determination. Patients were classified as responders if NYHA class was reduced by at least one level and echocardiographic ejection fraction (EF) increased ≥ 10%, and as super-responders if in NYHA class I and EF ≥ 50%. Forty patients (93% male, mean age 72 ± 10 years) were included. Thirty-three were programmed in Tri-V. The following results pertain to this subgroup. At baseline, 58% were in NYHA class III and 36% NYHA class II. At 1 year follow-up, Minnesota QoL score was reduced (36 ± 23 vs. 8 ± 6; P = 0.001) and the 6MWT distance improved (384 ± 120 m to 462 ± 87 m, P = 0.003). Mean EF increased (26% ± 8 vs. 39 ± 10; P < 0.001 at 6 months and 41 ± 10; P < 0.001 at 12 months). Responder rate was 59% at 6 months and 79% at 12 months. Super-responder rate was 9% at 6 months and 16% at 12 months. One year survival free from heart failure hospitalization was 87.9%. Conclusion: Tri-V CRT yielded higher response and super-response rates than usually reported for CRT in patients with permanent AF using clinical and remodeling criteria.

Hypercalcemic crisis and primary hyperparathyroidism: Cause of an unusual electrical storm. / Crise hipercalcémica e hiperparatiroidismo primário: causa de tempestade arrítmica invulgar.

Hypercalcemia is a known cause of heart rhythm disorders, however its association with ventricular arrhythmias is rare. The authors present a case of a fifty-three years old male patient with a ischemic and ethanolic dilated cardiomyopathy, and severely reduced ejection fraction, carrier of cardiac resynchronization therapy (CRT) with cardioverter defibrillator (ICD), admitted in the emergency department with an electrical storm, with multiple appropriated ICD shocks, refractory to antiarrhythmic therapy. In the etiological investigation was documented severe hypercalcemia secondary to primary hyperparathyroidism undiagnosed until then. Only after the serum calcium level reduction ventricular tachycardia was stopped.

Extracorporeal Circulatory Support in Acute Coronary Syndromes: A Systematic Review and Meta-Analysis.

OBJECTIVES: Extracorporeal circulatory support is a life-saving technique, and its use is increasing in acute coronary syndromes. A meta-analysis on pooled event rate of short-term mortality and complications of acute coronary syndrome patients treated with extracorporeal circulatory support was performed. DATA SOURCES: Articles were searched in MEDLINE, Cochrane Library, Google Scholar, and Biomed Central. STUDY SELECTION: Inclusion criteria were observational studies on acute coronary syndrome patients treated with extracorporeal circulatory support. Primary outcome was short-term mortality. Secondary outcomes were extracorporeal circulatory support-related complications, causes of death, long-term mortality, and bridge therapy. DATA EXTRACTION: Sixteen articles were selected. Data about clinical characteristics, acute coronary syndrome diagnosis and treatment, extracorporeal circulatory support setting, outcome definitions, and event rate were retrieved from the articles. Random effect meta-analytic pooling was performed reporting results as a summary point estimate and 95% CI. DATA SYNTHESIS: A total of 739 patients were included (mean age, 59.8 ± 2.9). The event rate of short-term mortality was 58% (95% CI, 51-64%), 6-month mortality was affecting 24% (95% CI, 5-63%) of 1-month survivors, and 1-year mortality 17% (95% CI, 6-40%) of 6-month survivors. The event rates of extracorporeal circulatory support-related complications were acute renal failure 41%, bleeding 25%, neurologic damage in survivors 21%, sepsis/infections 21%, and leg ischemia 12%. Between causes of death, multiple organ failure and brain death affected respectively 40% and 27% of patients. Bridge to ventricular assistance device was offered to 14% of patients, and 7% received a transplant. CONCLUSIONS: There is still a high rate of short-term mortality and complications in acute coronary syndrome patients treated with extracorporeal circulatory support. New studies are needed to optimize and standardize extracorporeal circulatory support.