Coronary physiology thresholds associated with microvascular obstruction in myocardial infarction.

OBJECTIVES: To ascertain whether invasive assessment of coronary physiology soon after recanalisation of the culprit artery by primary percutaneous coronary intervention is associated with the development of microvascular obstruction by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: Between November 2020 and December 2021, 102 consecutive patients were prospectively enrolled in five tertiary centres in Italy. Coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured in the culprit vessel soon after successful primary percutaneous coronary intervention. Optimal cut-off points of IMR and CFR to predict the presence of microvascular obstruction were estimated, stratifying the population accordingly in four groups. A comparison with previously proposed stratification models was carried out. RESULTS: IMR>31 units and CFR≤1.25 yielded the best accuracy. Patients with IMR>31 and CFR≤1.25 exhibited higher microvascular obstruction prevalence (83% vs 38%, p<0.001) and lower left ventricular ejection fraction (45±9% vs 52±9%, p=0.043) compared with those with IMR≤31 and CFR>1.25, and lower left ventricular ejection fraction compared with patients with CFR≤1.25 and IMR≤31 (45±9% vs 54±7%, p=0.025). Infarct size and area at risk were larger in the former, compared with other groups. CONCLUSIONS: IMR and CFR are associated with the presence of microvascular obstruction in STEMI. Patients with an IMR>31 units and a CFR≤1.25 have higher prevalence of microvascular obstruction, lower left ventricular ejection fraction, larger infarct size and area at risk. TRIAL REGISTRATION NUMBER: NCT04677257.

Clinical profiling and outcomes of viral myocarditis manifesting with ventricular arrhythmias.

Aims: Clinical features and risk stratification of patients with viral myocarditis (VM) complicated by ventricular arrhythmias (VA) are incompletely understood. We aim to describe arrhythmia patterns and outcomes in patients with VM and early-onset VA. Methods and results: We present a single-centre study, enrolling patients with VM proven by endomyocardial biopsy, and evidence of VA within 24 h of hospitalization. The incidence of major adverse events (MAE), including all-cause death, severe heart failure, advanced atrioventricular blocks, or major VA, was evaluated during a 24-month follow-up (FU) and compared with a matched group of virus-negative myocarditis. Of patients with VM (n = 74, mean age 47 ± 16 years, 66% males, and left ventricular ejection fraction 51 ± 13%), 20 (27%) presented with major VA [ventricular tachycardia/ventricular fibrillation (VT/VF)], and 32 (44%) had polymorphic VA. Patients with polymorphic VA more commonly had evidence of ongoing systemic infection (24/32 vs. 10/42, P = 0.004) and experienced greater occurrence of MAE at discharge (15/32 vs. 2/42, P < 0.001). However, the incidence of MAE during FU was higher in patients with monomorphic VA compared to those with polymorphic VA (17/42 vs. 2/28, P = 0.002). Patients with monomorphic VA displayed frequently signs of chronic cardiomyopathy and had outcomes comparable with virus-negative myocarditis (log rank P = 0.929). Presentation with VT/VF was independently associated with MAE [at discharge: hazard ratio (HR) 4.7, 95% confidence interval (CI) 1.6-14.0, P = 0.005; during FU: HR 6.3, 95% CI 2.3-17.6, P < 0.001]. Conclusion: In patients with VM, polymorphic VA point to ongoing systemic infection and early adverse outcomes, whereas monomorphic VA suggest chronic cardiomyopathy and greater incidence of MAE during FU. Presentation with VT/VF is independently associated with MAE.

Post-discharge arrhythmic risk stratification of patients with acute myocarditis and life-threatening ventricular tachyarrhythmias.

AIMS: The outcomes of patients presenting with acute myocarditis and life-threatening ventricular arrhythmias (LT-VA) are unclear. The aim of this study was to assess the incidence and predictors of recurrent major arrhythmic events (MAEs) after hospital discharge in this patient population. METHODS AND RESULTS: We retrospectively analysed 156 patients (median age 44 years; 77% male) discharged with a diagnosis of acute myocarditis and LT-VA from 16 hospitals worldwide. Diagnosis of myocarditis was based on histology or the combination of increased markers of cardiac injury and cardiac magnetic resonance (CMR) Lake Louise criteria. MAEs were defined as the relapse, after discharge, of sudden cardiac death or successfully defibrillated ventricular fibrillation, or sustained ventricular tachycardia (sVT) requiring implantable cardioverter-defibrillator therapy or synchronized external cardioversion. Median follow-up was 23 months [first to third quartile (Q1-Q3) 7-60]. Fifty-eight (37.2%) patients experienced MAEs after discharge, at a median of 8 months (Q1-Q3 2.5-24.0 months; 60.3% of MAEs within the first year). At multivariable Cox analysis, variables independently associated with MAEs were presentation with sVT [hazard ratio (HR) 2.90, 95% confidence interval (CI) 1.38-6.11]; late gadolinium enhancement involving ≥2 myocardial segments (HR 4.51, 95% CI 2.39-8.53), and absence of positive short-tau inversion recovery (STIR) (HR 2.59, 95% CI 1.40-4.79) at first CMR. CONCLUSIONS: Among patients discharged with a diagnosis of myocarditis and LT-VA, 37.2% had recurrences of MAEs during follow-up. Initial CMR pattern and sVT at presentation stratify the risk of arrhythmia recurrence.

The Spectrum of COVID-19-Associated Myocarditis: A Patient-Tailored Multidisciplinary Approach.

BACKGROUND: Myocarditis lacks systematic characterization in COVID-19 patients. METHODS: We enrolled consecutive patients with newly diagnosed myocarditis in the context of COVID-19 infection. Diagnostic and treatment strategies were driven by a dedicated multidisciplinary disease unit for myocarditis. Multimodal outcomes were assessed during prospective follow-up. RESULTS: Seven consecutive patients (57% males, age 51 ± 9 y) with acute COVID-19 infection received a de novo diagnosis of myocarditis. Endomyocardial biopsy was of choice in hemodynamically unstable patients (n = 4, mean left ventricular ejection fraction (LVEF) 25 ± 9%), whereas cardiac magnetic resonance constituted the first exam in stable patients (n = 3, mean LVEF 48 ± 10%). Polymerase chain reaction (PCR) analysis revealed an intra-myocardial SARS-CoV-2 genome in one of the six cases undergoing biopsy: in the remaining patients, myocarditis was either due to other viruses (n = 2) or virus-negative (n = 3). Hemodynamic support was needed for four unstable patients (57%), whereas a cardiac device implant was chosen in two of four cases showing ventricular arrhythmias. Medical treatment included immunosuppression (43%) and biological therapy (29%). By the 6-month median follow-up, no patient died or experienced malignant arrhythmias. However, two cases (29%) were screened for heart transplantation. CONCLUSIONS: Myocarditis associated with acute COVID-19 infection is a spectrum of clinical manifestations and underlying etiologies. A multidisciplinary approach is the cornerstone for tailored management.

3D imaging and morphometry of the heart capillary system in spontaneously hypertensive rats and normotensive controls.

Systemic arterial hypertension is a highly prevalent chronic disease associated with hypertensive cardiomyopathy. One important feature of this condition is remodelling of intramural small coronary arteries and arterioles. Here, we investigated the implications of this remodelling in the downstream vascular organization, in particular at the capillary level. We used Spontaneously Hypertensive Rats (SHR) exhibiting many features of the human hypertensive cardiomyopathy. We generated 3D high-resolution mesoscopic reconstructions of the entire network of SHR hearts combining gel-based fluorescent labelling of coronaries with a CLARITY-based tissue clearing protocol. We performed morphometric quantification of the capillary network over time to assess capillary diameter, linear density, and angular dispersion. In SHRs, we found significant remodelling of the capillary network density and dispersion. SHR capillary density is increased in both ventricles and at all ages, including before the onset of systemic hypertension. This result suggests that remodelling occurs independently from the onset of systemic hypertension and left ventricular hypertrophy. On the contrary, capillary angular dispersion increases with time in SHR. Consistently, our multicolor imaging underlined a strong correlation between vascular dispersion and cellular disarray. Together our data show that 3D high-resolution reconstruction of the capillary network can unveil anatomic signatures in both physiological and pathological cardiac conditions, thus offering a reliable method for integrated quantitative analyses.

Pulmonary hypertension and right ventricular involvement in hospitalised patients with COVID-19.

OBJECTIVE: To assess the prevalence, characteristics and prognostic value of pulmonary hypertension (PH) and right ventricular dysfunction (RVD) in hospitalised, non-intensive care unit (ICU) patients with coronavirus disease 2019 (COVID-19). METHODS: This single-centre, observational, cross-sectional study included 211 patients with COVID-19 admitted to non-ICU departments who underwent a single transthoracic echocardiography (TTE). Patients with poor acoustic window (n=11) were excluded. Clinical, imaging, laboratory and TTE findings were compared in patients with versus without PH (estimated systolic pulmonary artery pressure >35 mm Hg) and with versus without RVD (tricuspid annular plane systolic excursion <17 mm or S wave <9.5 cm/s). The primary endpoint was in-hospital death or ICU admission. RESULTS: A total of 200 patients were included in the final analysis (median age 62 (IQR 52-74) years, 65.5% men). The prevalence of PH and RVD was 12.0% (24/200) and 14.5% (29/200), respectively. Patients with PH were older and had a higher burden of pre-existing cardiac comorbidities and signs of more severe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (radiological lung involvement, laboratory findings and oxygenation status) compared with those without PH. Conversely, patients with RVD had a higher burden of pre-existing cardiac comorbidities but no evidence of more severe SARS-CoV-2 infection compared with those without RVD. The presence of PH was associated with a higher rate of in-hospital death or ICU admission (41.7 vs 8.5%, p<0.001), while the presence of RVD was not (17.2 vs 11.7%, p=0.404). CONCLUSIONS: Among hospitalised non-ICU patients with COVID-19, PH (and not RVD) was associated with signs of more severe COVID-19 and with worse in-hospital clinical outcome. TRIAL REGISTRATION NUMBER: NCT04318366.

Routine Screening of Coronary Artery Disease With Computed Tomographic Coronary Angiography in Place of Invasive Coronary Angiography in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Coronary artery disease (CAD) screening is required before transcatheter aortic valve implantation (TAVR). Although invasive coronary angiography (CA) remains the gold standard for CAD assessment, computed tomographic CA (CTCA) could be a safe and effective noninvasive alternative for CAD screening in patients undergoing TAVR. METHODS AND RESULTS: From November 2007 to May 2013, all patients undergoing TAVR at our institution were included in the study cohort. CTCA was used as first-line imaging tool for CAD screening. Invasive CA was performed when any of the following were present: coronary anatomy at CTCA was not evaluable and presence of significant CAD at CTCA. The primary objective was to compare major adverse cardiovascular and cerebrovascular events at 30 days and 1 year between patients who performed CTCA as only screening test and those who performed CTCA and invasive CA. Of 491 patients treated with TAVR, 375 (76.3%) performed only CTCA, whereas 116 (21.7%) underwent also CA. No differences were present in crude major adverse cardiovascular and cerebrovascular event rates at 30 days and 1 year between the 2 groups. After multivariable adjustment, CTCA performed alone was not associated with higher risk of MACE at 1 year of follow-up (hazard ratio, 0.89; 95% confidence interval, 0.49-1.60; P=0.69). CONCLUSIONS: CTCA performed as a routine noninvasive imaging tool in patients undergoing TAVR seems safe and effective allowing, with a single test, acquisition of information on aortic annulus anatomy, peripheral access sites, and evaluation of coronary anatomy.

Usefulness of baseline activated clotting time-guided heparin administration in reducing bleeding events during transfemoral transcatheter aortic valve implantation.

OBJECTIVES: This study sought to evaluate the impact of baseline activated clotting time (ACT)-guided heparin administration on major bleeding after transfemoral transcatheter aortic valve implantation (TAVI). BACKGROUND: Bleeding after TAVI is frequent and associated with unfavorable prognosis. Proper intraprocedural heparin dose administration may reduce the risk of potential overdosing in this frail study group. METHODS: Of the patients who underwent transfemoral TAVI in our center from November 1, 2007 to June 31, 2012, 362 were retrospectively analyzed. Because abnormally high baseline ACT values were noted, heparin was administered at the operator's discretion, according to baseline ACT (ACT-guided, n = 174) or patient's body weight (non-ACT-guided, n = 188). The primary study objective was 30-day major bleeding as defined by the Valve Academic Research Consortium criteria. Secondary objectives were any life-threatening, and minor bleeding, and other Valve Academic Research Consortium outcomes at 30 days. RESULTS: Bleeding occurred in 167 (46.1%) patients; of these, 76 (21.0%) had major bleeding. The ACT-guided group had a significantly lower occurrence of major (7.5% vs. 33.5%, p < 0.001), life-threatening (12.1% vs. 20.2%, p = 0.04), and any bleeding (25.9% vs. 64.9%, p < 0.001). Conversely, no differences were noted in the other study objectives. After adjustment for potential confounders, the protective odds ratio for ACT-guided therapy on major bleeding was 6.4 (95% confidence interval: 2.3 to 17.9; p < 0.001) at 30 days. CONCLUSIONS: In our experience, heparin administration according to baseline ACT was correlated with a significantly lower occurrence of major bleeding in transfemoral TAVI. This strategy might be a useful tool in reducing bleeding in this high-risk study group.