Diagnostic performance and prognostic impact of coronary angiography-based Index of Microcirculatory Resistance assessment: A systematic review and meta-analysis.

BACKGROUND: The Index of Microcirculatory Resistance (IMR), measured with a pressure-thermistor tipped coronary guidewire has been established as a gold standard for coronary microvascular assessment. Angiography-based IMR (angio-IMR) is a novel method to derive IMR without intracoronary instrumentation or the need for adenosine. METHODS: PubMed and Embase databases were systemically searched in November 2021 for studies that measured angio-IMR. The primary outcomes were pooled sensitivity and specificity as well as the area under the curve (AUC) of the summary receiver operating characteristic curve using IMR as a reference standard. RESULTS: A total of 129 records were initially identified and 8 studies were included in the final analysis. Overall, 1653 lesions were included in this study, of which 733 were in patients presenting with ST-segment elevation myocardial infarction. Angio-IMR yielded high diagnostic performance predicting wire-based IMR with pooled sensitivity = 0.81 (95% confidence interval: 0.76, 0.85), specificity = 0.80 (0.72, 0.86), and AUC = 0.86 (0.82, 0.88), which was similar irrespective of patient presentation. When the clinical outcome was compared between high versus low angio-IMR in patients presenting with myocardial infarction, high angio-IMR predicted an increased risk of major adverse cardiac events (MACE). CONCLUSION: Our study found that coronary angio-IMR has relatively high diagnostic performance as well as prognostic values predicting MACE, supporting its use in clinical practice.

Imaging Integration to Localize and Protect the Left Coronary Artery in Patients Undergoing LAAEI.

OBJECTIVES: This study sought to determine the distance between the anterior wall of the left atrial appendage (LAA) ostium to the left main coronary artery (LMCA) and the left circumflex artery (LCx) in patients undergoing left atrial appendage electrical isolation (LAAEI). BACKGROUND: LAAEI improves outcomes in nonparoxysmal atrial fibrillation ablation. There is a potential risk of damaging the LMCA and the LCx during LAAEI. METHODS: Patients undergoing LAAEI during the period between January 1, 2017 and October 31, 2018, were included in this study. Patients underwent cardiac computed tomography prior to ablation. The position of the LAA was analyzed. The closest distances between the LMCA, its bifurcation, LCx, and the anterior wall of the LAA ostium were measured. Additionally, imaging integration was performed to localize these vessels and catheter ablation was performed at least 5 mm away. RESULTS: A total of 74 patients (mean age: 68 ± 9.5 years; male 54%) who underwent LAAEI were included. The mean distance from the anterior wall of the LAA ostium to the LMCA was 7.88 ± 2.8 mm, to the LMCA bifurcation was 9.24 ± 4.40 mm, and to the LCx was 10.03 ± 4.56 mm. The LCx artery was found along the LAA ostium in 98% of the cases, whereas the LMCA was found in only 48.6%. No coronary damage or vasospasm was observed after performing LAAEI. CONCLUSIONS: A detailed imaging integration with cardiac computed tomography, electroanatomic mapping, and CARTOSOUND reconstructions to accurately define the anatomical relationship between the LMCA and LCx and the anterior edge of the LAA ostium should be performed prior to delivering radiofrequency energy during LAAEI. When the distance on cardiac computed tomography between the LAA ostium and left coronary arteries is >10 mm, intraprocedural localization of these vessels may be not necessary.

Mapping and localization of the left phrenic nerve during left atrial appendage electrical isolation to avoid inadvertent injury in patients undergoing catheter ablation of atrial fibrillation.

BACKGROUND: A significant role of the left atrial appendage (LAA) in the genesis of atrial fibrillation (AF) has been described. Left atrial appendage electrical isolation (LAAEI) confers substantial long-term clinical benefits. Nevertheless, the left phrenic nerve (LPN) is in the vicinity of the LAA and can be injured during radiofrequency ablation at the ostial level. OBJECTIVE: The purpose of this study was to describe our experience mapping the LPN, its anatomic relationships to the LAA and alternative approaches to isolate this structure when the LPN is located at the LAA ostium. METHODS: Patients undergoing LAAEI for nonparoxysmal AF were included in this study. We attempted to localize the LPN with high-output pacing (20 mA/2 ms). Cases were classified into 4 groups (distal, middle, proximal segment and unmappable) based on the position of the LPN in electroanatomic mapping in the posterior wall of the LAA. RESULTS: A total of 66 cases were included in this study. The LPN was mapped in the distal segment in 27 cases (40.9%); in the middle segment in 22 (33.3%); and at the proximal segment/ostium in 3 (4.5%); the LPN was unmappable in 14 cases (21.2%). In the 3 patients in whom the LPN was at the ostial level or crossing the ostium, segmental LAAEI was attempted in 2, with successful LAAEI achieved in 1 case. There was no LPN injury. CONCLUSION: LPN mapping is feasible and should be routinely performed to prevent LPN injury during LAAEI.

Safety of catheter ablation for atrial fibrillation in the octogenarian population.

INTRODUCTION: Catheter ablation (CA) has been shown to be an effective treatment for atrial fibrillation (AF). The complication rates and outcomes among octogenarians remain poorly studied. We aimed to compare trends, morbidity, and mortality associated with CA for AF among octogenarians versus those less than 80 years old. METHODS: Using weighted sampling from the National Inpatient Sample database, we identified patients with a primary diagnosis of AF and a primary procedure of CA (2004-2013). Our primary outcome was mortality. Secondary outcomes included incidence of major and minor complications. RESULTS: Among 86,119 patients who underwent CA for AF, 3,482 were 80 years old or older. Complications were significantly more frequent in octogenarians; [16.2% (564 of 3,482) versus 9.8% (8,092 of 82,637), P < 0.001]. Of note, there was no significant difference for the composite of major complications; [3.6% (124 of 3482) in octogenarians versus 2.8% (2286 of 82637), P = 0.20]. The total mortality rate was not significant in a multivariate regression analysis (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.35-2.64; P = .94). The presence of chronic renal failure (OR, 4.19; 95% CI, 2.75-6.36; P < 0.001), anemia (OR, 1.75; 95% CI, 1.03-2.97; P = .04), and chronic pulmonary disease (OR, 1.75; 95% CI, 1.11-2.62; P = .015) were predictors of major complications in octogenarians. CONCLUSION: Catheter ablation for AF in octogenarians does not confer a higher mortality risk than in those less than 80 years old. The procedure is associated with a higher rate of overall complications but there was no difference in terms of major complications or death. The presence of anemia, CKD or pulmonary disease were predictors of major complications in octogenarians.

Meta-Analysis and Trial Sequential Analysis Comparing Percutaneous Ventricular Assist Devices Versus Intra-Aortic Balloon Pump During High-Risk Percutaneous Coronary Intervention or Cardiogenic Shock.

The intra-aortic balloon pump (IABP) and percutaneous ventricular assist devices (pVAD) are commonly used in different clinical scenarios. The goal of this study was to carry out a meta-analysis and Trial Sequential Analysis (TSA) comparing the IABP versus pVAD (TandemHeart and the Impella) during high-risk percutaneous coronary intervention (PCI) or cardiogenic shock (CS). Using PubMed, Cochrane Central Register of Controlled Trials, and EMBASE we searched for randomized clinical trials (RCTs) and nonrandomized studies that compared pVAD versus IABP in patients who underwent high-risk PCI or with CS. We included 5 RCTs and 1 nonrandomized study comparing pVAD versus IABP. Based on the RCTs, we demonstrated no difference in short-term (6 months) (risk ratio [RR] 1.09, 95% confidence interval [CI] 0.79 to 1.52; p = 0.59) or long-term (12 months) (RR 1.00, 95% CI 0.57 to 1.76; p = 1.00) all-cause mortality. The use of pVAD seemed associated with more adverse events (acute kidney injury, limb ischemia, infection, major bleeding, and vascular injury) compared with IABP (RR 1.65, 95% CI 1.14 to 2.39; p = 0.008) but this was not supported by TSA (random-effects RR 1.66, 95% CI 0.89 to 3.09; p = 0.11; TSA-adjusted CI 0.13 to 21.3). In conclusion there were no differences in short or long-term mortality when using IABP versus pVAD for high-risk PCI or CS. IABP showed superiority over pVAD in terms of risk of harm. However, further RCTs are needed to establish more conclusively the role of these modalities of mechanical circulatory support during high-risk PCI or CS.