Estimation of coronary flow reserve by intracoronary administration of nicorandil: comparison with intracoronary administration of papaverine

Clinical implications of coronary microvascular dysfunction in patients with non-obstructive coronary artery disease and role of the thermodilution method

More than 60% of patients undergoing coronary angiography present no coronary artery disease (CAD). Angina and myocardial ischemia are classically determined by epicardial vascular obstruction, but coronary microvascular dysfunction (CMD) may also represent a possible cause for these phenomena. Two endotypes of CMD have been recognized, with two different pathophysiological mechanisms: structural CMD, characterized by low coronary flow reserve (CFR) and high microvascular resistance (MVR) values; and functional CMD, characterized by low CFR and normal MVR values. According to the present data, almost half of patients with non-obstructive CAD have shown signs of CMD. For this reason, further investigations for microvascular function assessment should be considered when evaluating no-CAD patients complaining of angina or presenting signs of myocardial ischemia. The thermodilution method is currently becoming a widespread invasive technique due to its feasibility and high reproducibility for coronary physiology evaluation. Furthermore, a recently introduced technique - called continuous thermodilution - allows for direct measurement of absolute coronary flow and resistances. The role of this brand-new technique in the clinical scenario is however still to be fully investigated and its use is at present limited to research purposes only. Among no-CAD patients, both structural and functional CMD are related to a worse prognosis in term of mortality and major adverse cardiovascular events (MACE). In this review, we will discuss the present evidence supporting the definition, prevalence and clinical implication of the different forms of CMD and the technical aspects of its invasive assessment.

Clinical use of physiological lesion assessment using pressure guidewires: an expert consensus document of the Japanese association of cardiovascular intervention and therapeutics-update 2022

Fractional flow reserve and instantaneous wave-free ratio are widely accepted and recommended in Western and Japanese guidelines for appropriate percutaneous coronary intervention. There are, however, many differences in clinical situations between Japan and Western countries. Therefore, the Task Force on coronary physiology of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has proposed an expert consensus document to summarize current evidence and suggest the practical use of physiological lesion assessment in Japan.

Summary of Torsades de Pointes (TdP) Reports Associated with Intravenous Drug Formulations Containing the Preservative Chlorobutanol

INTRODUCTION

Drug-induced torsades de pointes (TdP) is a potentially lethal ventricular arrhythmia that is associated with drugs that prolong the QT interval on the electrocardiogram (ECG) due to their interference with the cardiac potassium current, I_KR. Intravenous (IV) formulations of methadone have been associated with TdP and contain the preservative chlorobutanol, which, like methadone, blocks I_KR. The combinations of chlorobutanol with methadone or terfenadine, another I_KR blocker, produce synergistic I_KR block.

OBJECTIVE

The aim of this study was to examine and summarize the evidence available to address the question: what other IV drug formulations contain chlorobutanol and are they associated with TdP?

METHODS

IV drug products containing the preservative chlorobutanol were identified by searching the websites DailyMed ( https://dailymed.nlm.nih.gov/dailymed/index.cfm ) and Drugs@FDA ( https://www.accessdata.fda.gov/scripts/cder/daf/ ). For each drug identified, PubMed and the FDA's Adverse Event Reporting System (FAERS) were searched for reports of TdP and/or QT prolongation and FAERS data were analyzed for disproportionality of reports.

RESULTS

The search found nine drugs (methadone, epinephrine, papaverine, oxytocin, vasopressin, testosterone, estradiol, isoniazid, and desmopressin) that contain chlorobutanol 2.5 (n = 1) or 5.0 mg/mL. All nine drugs had reports of QT prolongation or TdP reported in FAERS and all but estradiol, testosterone, desmopressin, and isoniazid had reports of QT prolongation or TdP in PubMed. Two of the nine drugs (epinephrine and methadone) had positive signals (by disproportionality analysis) for TdP in FAERS (EB₀₅ 2.88 and 23.81, respectively) and four (methadone, epinephrine, papaverine, and vasopressin) were reported in published articles as the suspect drugs in cases of TdP.

CONCLUSION

The pharmacologic profile of chlorobutanol (synergistic I_KR block) and its association with reports of TdP and QT prolongation suggest the need for a full evaluation of its cardiac safety when used as a preservative in IV drug and vitamin formulations.

Effects of the Antianginal Drugs Ranolazine, Nicorandil, and Ivabradine on Coronary Microvascular Function in Patients With Nonobstructive Coronary Artery Disease: A Meta-analysis of Randomized Controlled Trials

PURPOSE

The goal of this study was to investigate the effects of the antianginal drugs ranolazine, nicorandil, and ivabradine on coronary microvascular function.

METHODS

Electronic scientific databases were searched for randomized trials investigating the effects of antianginal drugs on coronary microvascular function. Primary outcomes were changes in the coronary flow reserve (CFR), index of microvascular resistance (IMR), and myocardial perfusion reserve index (MPRI). The secondary outcome was the Seattle Angina Questionnaire scores. The standardized mean difference or weighted mean difference (WMD) (95% CI) served as a summary statistic.

FINDINGS

The antianginal drugs ranolazine, nicorandil, and ivabradine did not increase the CFR compared with the control drugs (standardized mean difference, 0.39; 95% CI, -0.08 to 0.85; P = 0.10). Ranolazine did not increase the global MPRI compared with the control drugs (weighted mean difference [WMD], 0.11; 95% CI, -0.06 to 0.29; P = 0.21). However, in the subgroups with a baseline CFR <2.5 or a global MPRI <2, ranolazine increased the global MPRI (WMD, 0.19; 95% CI, 0.10 to 0.27; P < 0.0001). In addition, the subendocardial midventricular MPRI (mid-subendocardial MPRI) was improved after ranolazine treatment (WMD, 0.12; 95% CI, 0.03 to 0.20; P = 0.007). Moreover, nicorandil significantly reduced the IMR compared with the control drugs (WMD, -7.63; 95% CI, -11.82 to -3.44; P = 0.0004). In addition, ranolazine and ivabradine improved 3 of the 5 Seattle Angina Questionnaire scores.

IMPLICATIONS

Ranolazine improved the global MPRI in patients with definite coronary microvascular dysfunction and the mid-subendocardial MPRI with suspicious coronary microvascular dysfunction, and nicorandil reduced the IMR. In addition, ranolazine and ivabradine reduced angina. Moreover, it is possible that the IMR and mid-subendocardial MPRI are more sensitive than the CFR and global MPRI for evaluating coronary microvascular function.

Clinical use of physiological lesion assessment using pressure guidewires: an expert consensus document of the Japanese Association of Cardiovascular Intervention and Therapeutics

In this document, the background, concept, and current evidence are briefly summarized. The focus is on the clinical application of physiological lesion assessment from a practical standpoint for facilities that do not have ample experience. Finally, the characteristics of new resting indexes are summarized.

Measuring Procedure and Maximal Hyperemia in the Assessment of Fractional Flow Reserve for Superficial Femoral Artery Disease

AIM

The optimal fractional flow reserve (FFR) measurement method for superficial femoral artery (SFA) lesions remains to be established. We clarified the optimal measuring procedure for FFR for SFA lesions and investigated the necessary dose of papaverine for inducing maximal hyperemia in SFA lesions.

METHODS

Forty-eight patients with SFA lesions who underwent measurement of peripheral FFR (pFFR: distal mean pressure divided by proximal mean pressure) after endovascular treatment by the contralateral femoral crossover approach were prospectively enrolled. In the pFFR measurement, a guide sheath was placed on top of the common iliac bifurcation and pressure equalization was performed. After advancing the pressure wire distal to the SFA lesion, sequential papaverine administration selectively to the affected common iliac artery was performed.

RESULTS

There were no symptoms, electrocardiogram changes, and significant pressure drops at the guide sheath tip with increasing papaverine dose. pFFR changes following 20, 30, and 40 mg of papaverine were 0.87±0.10, 0.84±0.10, and 0.84±0.10, respectively (P＜0.001). Although not significantly different, pFFR decreased more in several patients at 30 mg of papaverine than at 20 mg. The pFFR at 40 mg of papaverine was almost similar to that at 30 mg of papaverine. The necessary papaverine dose was not changed according to sex and number of run-off vessels.

CONCLUSIONS

The contralateral femoral crossover approach is useful in FFR measurement for SFA lesions, and maximal hyperemia is induced by 30 mg of papaverine.

ST elevation after intracoronary administration of Papaverine for fractional flow reserve estimation

INTRODUCTION

Intracoronary (IC) papaverine which is one of the commonly used agents for Fractional Flow Reserve (FFR) estimation has been reported to cause transient ST elevation in some patients. This phenomenon has not been systematically studied.

MATERIAL AND METHODS

This is a prospective, observational study. Consecutive patients, who underwent FFR at our institute using IC papaverine from May 2012 to April 2013, were included. FFR was done when clinically indicated. The procedure involved administration of 20 mg papaverine (Paparin)--Troikaa, Ahmedabad) as a fast bolus by intracoronary route followed by a 10 cc contrast flush, following which pressure measurements were made. Continuous ECG recording by Philips Hemodynamic Laboratory was obtained for all patients throughout the procedure. Post procedure, they were observed for any delayed effects and eventual outcome was documented. Fischer's mid-p test was used for statistical analysis.

RESULT

Twenty-five patients (18 males, 7 females, mean age 57.9 ± 20 years) underwent FFR using Papaverine. The mean LVEF was (51 ± 15%). Fourteen patients (56%) developed transient ST elevation ≥0.5 mm in one or more leads which resolved spontaneously in all cases without any sequelae. The presence of a significant lesion either in the coronary artery being evaluated or in a remote coronary artery did not predict the ST elevation. 70.5% of diabetics (p = 0.02), 75% of hypertensives (p = 0.008) and 75% of patients with LVH (p = 0.008) had ST elevation. None of the 5 patients without any one of these comorbidities showed ST elevation.

CONCLUSION

Transient ST elevation occurs in a significant proportion of cases receiving IC papaverine which is not associated with any adverse clinical outcomes. Micro vascular dysfunction is the most likely mechanism of this phenomenon.

A case of vasospastic angina in which the ergonovine provocation test with intracoronary isosorbide dinitrate and nicorandil was effective in the diagnosis of microvascular spasm

A 60-year-old man was admitted with early morning angina while at rest. Coronary angiogram revealed no organic lesions; therefore, a spasm provocation test with ergonovine was performed. Administration of intracoronary ergonovine induced total occlusion of the right coronary artery. The induced total occlusion improved but coronary flow velocity remained severely reduced and chest discomfort with ST-T changes in ECG remained in spite of repeated administration of isosorbide dinitrate (ISDN). Intracoronary administration of nicorandil following ISDN alleviated the chest discomfort, normalized the ST-T change in ECG, and improved the coronary flow. This suggested that microvascular spasm and the epicardial spasm were not relieved by ISDN but by nicorandil. Intracoronary nicorandil injection following ISDN administration may be useful for the diagnosis of microvascular spasm in the ergonovine provocation test.

Coronary microvascular abnormality in the reversible systolic dysfunction observed after noncardiac disease

Acute reversible left ventricular wall motion abnormalities mimicking myocardial stunning have been reported with noncardiac disease and their coronary angiograms did not demonstrate organic stenosis or vasospasm in the epicardial coronary arteries. Thus, this mechanism has not yet been fully clarified. Two patients are reported as demonstrating acute reversible wall motion abnormalities after noncardiac disease. The electrocardiographic and echocardiographic findings mimicked myocardial stunning and confirmed the previous reports. The coronary angiograms did not show any corresponding coronary stenosis or vasospasm, but did show a reduced coronary flow reserve. Cardiac metaiodobenzylguanidine scintigraphy demonstrated regional defects involving the apex, a decreased heart/mediastinum ratio and an enhanced washout rate, which partially returned to normal after 3 months. Microvascular dysfunction and sympathetic nervous abnormalities might be responsible for the reversible contractile impairment.