A systematic screening and heart team approach contributes to unravel novel risk factors in revascularisation candidates of complex coronary artery disease: a machine learning approach.

INTRODUCTION: The baseline characteristics affecting mortality following percutaneous or surgical revascularisation in patients with left main (LM) and/or three-vessel (3V) coronary artery disease (CAD) differ between real-world practice and those established in randomized control trials (RCT) due to the constraints of inclusion/exclusion criteria. OBJECTIVES: This study aimed to assess whether systematic screening identifies novel and registry-specific baseline characteristics influencing long-term mortality. PATIENT AND METHODS: LASSO (Least Absolute Shrinkage and Selection Operator) regression was used to screen 42 baseline characteristics shared by the SYNTAX trial and a single-center Polish registry of 1035 consecutive patients with complex CAD, receiving revascularization and followed up for 5 years. After screening, classical Cox regression analysis was performed to examine the suitability of a Linear model for predicting 5-year mortality, which was then compared to the mortality predicted in the same cohort using the SYNTAX score 2020 (SS2020). RESULTS: Five-year mortality in the registry was 12.3%, with the strongest predictors of pulmonary hypertension, chronic obstructive pulmonary disease and insulin-dependent diabetes. In an internal validation, the linear model constructed after LASSO screening and combined with a classical Cox regression analysis improved the prediction of 5-year mortality compared to the SS2020 (c-index 0.92 and 0.75, respectively). CONCLUSIONS: Machine learning improved the detection of registry-specific risk factors in all comers patients amenable to surgical or percutaneous revascularization who were discussed in a heart team. The risk factors identified from RCT are not necessarily the same as those detected in real clinical practice when systematic screening is applied.

Quantitative coronary computed tomography assessment for differentiating between total occlusions and severe stenoses.

BACKGROUNDS: The impact of quantitative assessment to differentiate total occlusions (TOs) from severe stenoses on coronary computed tomography angiography (CCTA) remains unknown. OBJECTIVE: This study investigated whether quantitative characteristics assessed on CCTA could help differentiate a TO from a severe stenosis on invasive coronary angiography (ICA). METHODS: This study is a sub-analysis of the FASTTRACK CABG (NCT04142021) in which both CCTA and ICA were routinely performed. Quantitative analysis was performed with semi-automated CCTA plaque-analysis software. Blinded analysts compared TOs on CCTA, defined as a complete lack of contrast opacification within the coronary occlusion, with corresponding ICA. RESULTS: Eighty-four TOs were seen on CCTA in 59 of the 114 patients enrolled in the trial. The concordance in diagnosing a TO between ICA and CCTA was 56.0% (n â€‹= â€‹47). Compared to severe stenoses, TOs had a significantly longer lesion length (25.1 â€‹± â€‹23.0 â€‹mm vs 9.4 â€‹± â€‹11.2 â€‹mm, P â€‹< â€‹0.001). The best cut-off value to differentiate a TO from severe stenosis was a lesion length of 5.5 â€‹mm (area under the curve 0.77, 95% CI: 0.66-0.87), with a 91.1% sensitivity and 61.1% specificity. Dense calcium percentage atheroma volume (PAV) was significantly higher in TOs compared to severe stenoses (18.7 â€‹± â€‹19.6% vs. 6.6 â€‹± â€‹13.0%, P â€‹< â€‹0.001), whilst the opposite was seen for fibro-fatty PAV (31.3 â€‹± â€‹14.2% vs. 19.5 â€‹± â€‹10.5%, P â€‹< â€‹0.001). On a multivariable logistic regression analysis, lesion length (>5.5 â€‹mm) was the only parameter associated with differentiating a TO from a severe stenosis. CONCLUSION: In quantitative CCTA analysis, a lesion length >5.5 â€‹mm was the only independent predictor differentiating a TO from a severe stenosis. NCT REGISTRATION NUMBER: NCT04142021.

Editorial: Is the axiom of balloon angioplasty, "the more you gain the more you lose", still true in the era of DCB with paclitaxel?

Balloon angioplasty achieves luminal enlargement by fracturing the atherosclerotic intima at its point of least resistance, thereby creating a dissection plane and space with dehiscence of the intima from the media. This barotraumatic dissection triggers an inflammatory and proliferative reaction, resulting in a restenosis process at medium-term. In the era of plain old balloon angioplasty, quantitative angiographic studies at follow-up demonstrated that - the greater the acute luminal gain was after balloon angioplasty, the greater the late luminal loss was at follow-up. The interventional cardiologists coined the following motto "the more you gain, the more you lose". However, in the current era of drug coated balloon (DCB), it appears that this vexing conundrum could have been abrogated. A recently published DCB study in small de novo vessel has demonstrated that there was a slightly negative correlation between the volume of dissection assessed by optical coherence tomography and the angiographic late luminal loss (now gain) after Paclitaxel coated balloon treatment. In other words, the barotraumatic dissection does not necessarily herald a restenosis process in the era of DCB. This article revisits the mechanism of balloon angioplasty and explores how DCB with Paclitaxel may change the paradigm of balloon angioplasty as default treatment in CAD percutaneous treatment.

γ-Glutamyl Transferase and Long-Term Survival in the SYNTAXES Trial: Is It Just the Liver?

BACKGROUND: Recently, machine learning algorithms have identified preprocedural γ-glutamyl transferase (GGT) as a significant predictor of long-term mortality after coronary revascularization in the SYNTAX (Synergy Between PCI [Percutaneous Coronary Intervention] With Taxus and Cardiac Surgery) trial. The aim of the present study is to investigate the impact of preprocedural GGT on 10-year all-cause mortality in patients with complex coronary artery disease after revascularization. METHODS AND RESULTS: The SYNTAX trial was a randomized trial comparing PCI with coronary artery bypass grafting in 1800 patients with complex coronary artery disease. The present report is a post hoc subanalysis of the SYNTAXES (Synergy Between PCI With Taxus and Cardiac Surgery Extended Survival) trial, an investigator-driven extended 10-year follow-up of the SYNTAX trial. The association between preprocedural GGT and 10-year all-cause mortality was investigated. The mean values of GGT for men and women were 43.5 (SD, 48.5) and 36.4 (SD, 46.1) U/L, respectively. In multivariable Cox regression models adjusted by traditional risk factors, GGT was an independent predictor for all-cause death at 10-year follow-up, and each SD increase in log-GGT was associated with a 1.24-fold risk of all cause death at 10-year follow-up (95% CI, 1.10-1.40). According to previously reported sex-related GGT thresholds, patients with higher GGT level had a 1.74-fold risk of all-cause death at 10-year follow-up (95% CI, 1.32-2.29) compared with patients with lower GGT level. CONCLUSIONS: Preprocedural GGT is an independent predictor of 10-year mortality after coronary revascularization in patients with complex coronary artery disease. In patients with elevated GGT, strong secondary prevention may be required after revascularization and must be studied prospectively. REGISTRATION: URL: https://clinicaltrials.gov/study/NCT03417050.

Coronary bypass surgery guided by computed tomography in a low-risk population.

BACKGROUND AND AIMS: In patients with three-vessel disease and/or left main disease, selecting revascularization strategy based on coronary computed tomography angiography (CCTA) has a high level of virtual agreement with treatment decisions based on invasive coronary angiography (ICA). METHODS: In this study, coronary artery bypass grafting (CABG) procedures were planned based on CCTA without knowledge of ICA. The CABG strategy was recommended by a central core laboratory assessing the anatomy and functionality of the coronary circulation. The primary feasibility endpoint was the percentage of operations performed without access to the ICA. The primary safety endpoint was graft patency on 30-day follow-up CCTA. Secondary endpoints included topographical adequacy of grafting, major adverse cardiac and cerebrovascular (MACCE), and major bleeding events at 30 days. The study was considered positive if the lower boundary of confidence intervals (CI) for feasibility was ≥75% (NCT04142021). RESULTS: The study enrolled 114 patients with a mean (standard deviation) anatomical SYNTAX score and Society of Thoracic Surgery score of 43.6 (15.3) and 0.81 (0.63), respectively. Unblinding ICA was required in one case yielding a feasibility of 99.1% (95% CI 95.2%-100%). The concordance and agreement in revascularization planning between the ICA- and CCTA-Heart Teams was 82.9% with a moderate kappa of 0.58 (95% CI 0.50-0.66) and between the CCTA-Heart Team and actual treatment was 83.7% with a substantial kappa of 0.61 (95% CI 0.53-0.68). The 30-day follow-up CCTA in 102 patients (91.9%) showed an anastomosis patency rate of 92.6%, whilst MACCE was 7.2% and major bleeding 2.7%. CONCLUSIONS: CABG guided by CCTA is feasible and has an acceptable safety profile in a selected population of complex coronary artery disease.

Impact of Coronary Microvascular Dysfunction on Functional Left Ventricular Remodeling and Diastolic Dysfunction.

BACKGROUND: Coronary microvascular dysfunction (CMD) is a common complication of ST-segment-elevation myocardial infarction (STEMI) and can lead to adverse cardiovascular events. Whether CMD after STEMI is associated with functional left ventricular remodeling (FLVR) and diastolic dysfunction, has not been investigated. METHODS AND RESULTS: This is a nonrandomized, observational, prospective study of patients with STEMI with multivessel disease. Coronary flow reserve and index of microcirculatory resistance of the culprit vessel were measured at 3 months post-STEMI. CMD was defined as index of microcirculatory resistance ≥25 or coronary flow reserve <2.0 with a normal fractional flow reserve. We examined the association between CMD, LV diastolic dysfunction, FLVR, and major adverse cardiac events at 12-month follow-up. A total of 210 patients were enrolled; 59.5% were men, with a median age of 65 (interquartile range, 58-76) years. At 3-month follow-up, 57 patients (27.14%) exhibited CMD. After 12 months, when compared with patients without CMD, patients with CMD had poorer LV systolic function recovery (-10.00% versus 8.00%; P<0.001), higher prevalence of grade 2 LV diastolic dysfunction (73.08% versus 1.32%; P<0.001), higher prevalence of group 3 or 4 FLVR (11.32% versus 7.28% and 22.64% versus 1.99%, respectively; P<0.001), and higher incidence of major adverse cardiac events (50.9% versus 9.8%; P<0.001). Index of microcirculatory resistance was independently associated with LV diastolic dysfunction and adverse FLVR. CONCLUSIONS: CMD is present in ≈1 of 4 patients with STEMI during follow-up. Patients with CMD have a higher prevalence of LV diastolic dysfunction, adverse FLVR, and major adverse cardiac events at 12 months compared with those without CMD. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT05406297.

Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting in Patients With Left Main Disease With and Without Diabetes: Findings From a Pooled Analysis of 4 Randomized Clinical Trials.

BACKGROUND: Diabetes may be associated with differential outcomes in patients undergoing left main coronary revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). The aim of this study was to investigate outcomes in patients with left main disease with and without diabetes randomized to PCI versus CABG. METHODS: Individual patient data were pooled from 4 trials (SYNTAX [Synergy Between PCI With Taxus and Cardiac Surgery], PRECOMBAT [Premier of Randomized Comparison of Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease], NOBLE [Nordic-Baltic-British Left Main Revascularisation Study], and EXCEL [Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization]) that randomized patients with left main disease to PCI or CABG. Patients were considered suitable for either approach. Patients were categorized by diabetes status. Kaplan-Meier event rates, Cox model hazard ratios, and interactions were assessed. RESULTS: Among 4393 patients, 1104 (25.1%) had diabetes. Patients with diabetes experienced higher rates of 5-year death (158/1104 [Kaplan-Meier rate, 14.7%] versus 297/3289 [9.3%]; P<0.001), spontaneous myocardial infarction (MI; 67/1104 [6.7%] versus 114/3289 [3.7%]; P<0.001), and repeat revascularization (189/1104 [18.5%] versus 410/3289 [13.2%]; P<0.001). Rates of all-cause mortality did not differ after PCI versus CABG in those with (84/563 [15.3%] versus 74/541 [14.1%]; hazard ratio, 1.11 [95% CI, 0.82-1.52]) or without (155/1634 [9.7%] versus 142/1655 [8.9%]; hazard ratio, 1.08 [95% CI, 0.86-1.36; PintHR=0.87) diabetes. Rates of stroke within 1 year were lower with PCI versus CABG in the entire population, with no heterogeneity based on diabetes status (PintHR=0.51). The 5-year rates of spontaneous MI and repeat coronary revascularization were higher after PCI regardless of diabetes status (spontaneous MI: 45/563 [8.9%] versus 22/541 [4.4%] in diabetes and 82/1634 [5.3%] versus 32/1655 [2.1%] in no diabetes, PintHR=0.47; repeat revascularization: 127/563 [24.5%] versus 62/541 [12.4%] in diabetes and 254/1634 [16.3%] versus 156/1655 [10.1%] in no diabetes, PintHR=0.18). For spontaneous MI and repeat revascularization, there were greater absolute risk differences beyond 1 year in patients with diabetes (4.9% and 9.9%) compared with those without (2.1% and 4.3%; PintARD=0.047 and 0.016). CONCLUSIONS: In patients with left main disease considered equally suitable for PCI or CABG and with largely low to intermediate SYNTAX scores, diabetes was associated with higher rates of death and cardiovascular events through 5 years. Compared with CABG, PCI resulted in no difference in the risk of death and a lower risk of early stroke regardless of diabetes status, and a higher risk of spontaneous MI and repeat coronary revascularization, with larger late absolute excess risks in patients with diabetes. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01205776, NCT0146651, NCT00422968, and NCT00114972.

Impact of Incomplete Revascularization After PCI in Left Main Disease: The EXCEL Trial.

BACKGROUND: The importance of complete revascularization after percutaneous coronary intervention (PCI) in patients with left main coronary artery disease is uncertain. We investigated the clinical impact of complete revascularization in patients with left main coronary artery disease undergoing PCI in the EXCEL trial (Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization). METHODS: Composite rates of death or myocardial infarction (MI) following PCI during 5-year follow-up were examined in 903 patients based on core laboratory definitions of anatomic and functional complete revascularization, residual SYNTAX score (The Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery), and residual Jeopardy Score (rJS). RESULTS: The risk of death or MI did not vary based on anatomic, functional, or residual SYNTAX score complete revascularization but did differ according to the rJS (5-year rates 17.6%, 19.5%, and 38.9% with rJS 0, 2, and ≥4, respectively; P=0.006). The higher rate of death or MI with rJS≥4 versus rJS≤2 was driven conjointly by increased mortality (adjusted hazard ratio, 2.29 [95% CI, 1.11-4.71]; P=0.02) and spontaneous MI (adjusted hazard ratio, 2.89 [95% CI, 1.17-7.17]; P=0.02). The most common location for untreated severe stenoses in the rJS≥4 group was the left circumflex artery (LCX), and the post-PCI absence, compared with the presence, of any untreated lesion with diameter stenosis ≥70% in the LCX was associated with reduced 5-year rates of death or MI (18.9% versus 35.2%; hazard ratio, 0.48 [95% CI, 0.32-0.74]; P<0.001). The risk was the highest for residual ostial/proximal LCX lesions. CONCLUSIONS: Among patients undergoing PCI in EXCEL trial, incomplete revascularization according to the rJS was associated with increased rates of death and spontaneous MI. Post-PCI untreated high-grade lesions in the LCX (especially the ostial/proximal LCX) drove these outcomes. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01205776.

Incidence, Predictors, and Impact of Hospital Readmission After Revascularization for Left Main Coronary Disease.

BACKGROUND: The frequency of and relationship between hospital readmissions and outcomes after revascularization for left main coronary artery disease (LMCAD) are unknown. OBJECTIVES: The purpose of this study was to study the incidence, predictors, and clinical impact of readmissions following percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for LMCAD. METHODS: In the EXCEL (XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial, 1,905 patients with LMCAD were randomized to PCI vs CABG. The cumulative incidence of readmissions was analyzed with multivariable Anderson-Gill and joint frailty models to account for recurrent events and the competing risk of death. The impact of readmission on subsequent mortality within 5-year follow-up was determined in a time-adjusted Cox proportional hazards model. RESULTS: Within 5 years, 1,868 readmissions occurred in 851 of 1,882 (45.2%) hospital survivors (2.2 ± 1.9 per patient with readmission[s], range 1-16), approximately one-half for cardiovascular causes and one-half for noncardiovascular causes (927 [49.6%] and 941 [50.4%], respectively). One or more readmissions occurred in 463 of 942 (48.6%) PCI patients vs 388 of 940 (41.8%) CABG patients (P = 0.003). After multivariable adjustment, PCI remained an independent predictor of readmission (adjusted HR: 1.22; 95% CI: 1.10-1.35; P < 0.0001), along with female sex, comorbidities, and the extent of CAD. Readmission was independently associated with subsequent all-cause death, with interaction testing indicating a higher risk after PCI than CABG (adjusted HR: 5.72; 95% CI: 3.42-9.55 vs adjusted HR: 2.72; 95% CI: 1.64-4.88, respectively; Pint = 0.03). CONCLUSIONS: In the EXCEL trial, readmissions during 5-year follow-up after revascularization for LMCAD were common and more frequent after PCI than CABG. Readmissions were associated with an increased risk of all-cause death, more so after PCI than with CABG.

Prasugrel Monotherapy After Percutaneous Coronary Intervention for Chronic Coronary Syndrome: Insights From ASET Pilot Studies.

Background: The ASET (Acetyl-Salicylic Elimination Trial) pilot studies recently investigated P2Y12 inhibitor monotherapy without aspirin immediately after percutaneous coronary intervention (PCI) in Brazil and Japan. Objectives: This comparative analysis of the 2 ASET pilot studies aimed to summarize clinical outcomes and assess geographic and ethnic differences in baseline demographics and procedures. Methods: Patients undergoing successful platinum-chromium everolimus-eluting stent implantation for chronic coronary syndrome were included. Following the index PCI, patients received prasugrel monotherapy with a maintenance dose of 10 mg/day in Brazil and 3.75 mg/day in Japan. The primary ischemic endpoint was the composite of cardiac death, spontaneous target vessel myocardial infarction, or definite stent thrombosis. The primary bleeding endpoint was Bleeding Academic Research Consortium types 3 and 5 bleeding at up to 3 months. Results: Of 409 enrollments, 3-month follow-up was completed in 406 patients. Mean age was 64.3 ± 8.4 years, and 73% were men. Overall, post-TIMI flow grade 3 was achieved in 99.8%. Intravascular imaging for poststent optimization was used in 16.8% and 99.6% of treated lesions in Brazil and Japan, respectively. The primary ischemic and bleeding endpoints occurred in the same patient (0.2%). No stent thrombosis events occurred. Conclusions: Prasugrel monotherapy following PCI was safe and feasible in selected low-risk chronic coronary syndrome patients after optimal platinum-chromium everolimus-eluting stent implantation regardless of the ethnic and geographic differences in baseline demographics, procedures, and prasugrel dosage. Randomized controlled trials will be needed to compare P2Y12 inhibitor monotherapy without aspirin with the current standard of care.

Ticagrelor or Clopidogrel Monotherapy vs Dual Antiplatelet Therapy After Percutaneous Coronary Intervention: A Systematic Review and Patient-Level Meta-Analysis.

Importance: Among patients undergoing percutaneous coronary intervention (PCI), it remains unclear whether the treatment efficacy of P2Y12 inhibitor monotherapy after a short course of dual antiplatelet therapy (DAPT) depends on the type of P2Y12 inhibitor. Objective: To assess the risks and benefits of ticagrelor monotherapy or clopidogrel monotherapy compared with standard DAPT after PCI. Data Sources: MEDLINE, Embase, TCTMD, and the European Society of Cardiology website were searched from inception to September 10, 2023, without language restriction. Study Selection: Included studies were randomized clinical trials comparing P2Y12 inhibitor monotherapy with DAPT on adjudicated end points in patients without indication to oral anticoagulation undergoing PCI. Data Extraction and Synthesis: Patient-level data provided by each trial were synthesized into a pooled dataset and analyzed using a 1-step mixed-effects model. The study is reported following the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data. Main Outcomes and Measures: The primary objective was to determine noninferiority of ticagrelor or clopidogrel monotherapy vs DAPT on the composite of death, myocardial infarction (MI), or stroke in the per-protocol analysis with a 1.15 margin for the hazard ratio (HR). Key secondary end points were major bleeding and net adverse clinical events (NACE), including the primary end point and major bleeding. Results: Analyses included 6 randomized trials including 25 960 patients undergoing PCI, of whom 24 394 patients (12 403 patients receiving DAPT; 8292 patients receiving ticagrelor monotherapy; 3654 patients receiving clopidogrel monotherapy; 45 patients receiving prasugrel monotherapy) were retained in the per-protocol analysis. Trials of ticagrelor monotherapy were conducted in Asia, Europe, and North America; trials of clopidogrel monotherapy were all conducted in Asia. Ticagrelor was noninferior to DAPT for the primary end point (HR, 0.89; 95% CI, 0.74-1.06; P for noninferiority = .004), but clopidogrel was not noninferior (HR, 1.37; 95% CI, 1.01-1.87; P for noninferiority > .99), with this finding driven by noncardiovascular death. The risk of major bleeding was lower with both ticagrelor (HR, 0.47; 95% CI, 0.36-0.62; P < .001) and clopidogrel monotherapy (HR, 0.49; 95% CI, 0.30-0.81; P = .006; P for interaction = 0.88). NACE were lower with ticagrelor (HR, 0.74; 95% CI, 0.64-0.86, P < .001) but not with clopidogrel monotherapy (HR, 1.00; 95% CI, 0.78-1.28; P = .99; P for interaction = .04). Conclusions and Relevance: This systematic review and meta-analysis found that ticagrelor monotherapy was noninferior to DAPT for all-cause death, MI, or stroke and superior for major bleeding and NACE. Clopidogrel monotherapy was similarly associated with reduced bleeding but was not noninferior to DAPT for all-cause death, MI, or stroke, largely because of risk observed in 1 trial that exclusively included East Asian patients and a hazard that was driven by an excess of noncardiovascular death.

Five-year outcomes in patients with multivessel coronary artery disease undergoing surgery or percutaneous intervention.

The outcomes from real-life clinical studies regarding the optimal revascularization strategy in patients with multivessel coronary artery disease (MVD) are still poorly investigated. In this retrospective study we assessed 5-year outcomes: primary, secondary endpoints and quality of life of 1035 individuals with severe coronary artery disease (CAD) treated either with coronary artery bypass grafting (CABG)-356 patients or percutaneous coronary intervention (PCI)-679 patients according to the recommendation of a local Heart Team (HT). At 5 years no significant difference in overall mortality and rates of myocardial infarctions (MI) were observed between CABG and PCI cohorts (11.0% vs. 13.4% for PCI, P = 0.27 and 9.6% vs. 12.8% for PCI, P = 0.12, respectively). The incidence of major adverse cardiac and cerebrovascular events (MACCE), mainly driven by increased rates of repeat revascularization (RR) were higher in PCI-cohort than in CABG-group (56.1% vs. 40.4%, P < 0.01 and 26.8% vs. 12.6%, P < 0.01, respectively), while CABG-patients experienced stroke more often (7.3% vs. 3.1% for PCI, P < 0.01). In real-life practice with long-term follow-up, none of the two revascularization modalities implemented following HT decisions showed overwhelming superiority: occurrence of death and MI were similar, rates of RR favoured CABG, while incidence of strokes advocated PCI.

Percutaneous Alginate Hydrogel Endomyocardial Injection with a Novel Dedicated Catheter Delivery System: An Animal Feasibility Study.

The objective of this preclinical study was to evaluate the feasibility and safety of transcatheter endocardial alginate hydrogel injection (TEAi) in a large animal model, utilizing the high-stiffness XDROP® alginate hydrogel in combination with the dedicated EndoWings® catheter-based system. All swine (n = 9) successfully underwent TEAi without complications. Acute results from a subset of animals (n = 5) demonstrated the ability of the catheter to access a wide range of endomyocardial areas and achieve consecutive circumferential hydrogel distribution patterns within the mid-left ventricular wall. Histological examinations at 6 months (n = 4) demonstrated that the XDROP® remained localized within the cardiac tissue. In addition, serial echocardiographic imaging showed that XDROP® had no adverse impacts on LV systolic and diastolic functions. In conclusion, this innovative combination technology has the potential to overcome the translational barriers related to alginate hydrogel delivery to the myocardium.