Absence of postprandial surge in coronary blood flow distal to significant stenosis: a possible mechanism of postprandial angina

Siddha fasting in obese acute decompensated heart failure may improve hospital outcomes through empowerment and natural ketosis

BACKGROUND

Morbid obesity (BMI > 35 kg/m2 with comorbid conditions) is present in 25 - 35% of acute decompensated heart failure (AHF) patients. Prevalence of HF increases with duration of morbid obesity from 30% at 15 years to over 90% at 30 years. There is a need to develop pragmatic therapies that address the unique physical and mental challenges faced by obese AHF patients. Siddha is 5,000 year old Tamil Medicine using yoga and mind-body methods towards higher consciousness. Hunger gratitude Experience (HUGE) is intuitive Siddha fasting method which may improve in-hospital AHF outcomes independent of weight reduction.

CASE SUMMARY

We present 5 cases of morbidly obese patients with cardiorenal syndrome (CRS) that began intermittent fasting either during their AHF hospitalization or in the outpatient setting for refractory symptoms despite hospitalization. Initiation of fasting correlated with reduction of respiratory distress and edema as well as improvements in psychological wellbeing and functional capacity.

DISCUSSION

Siddha fasting mediates hemodynamic and anti-inflammatory effects through natural ketosis and psychological benefits through empowerment in AHF. Potential role of fasting in reducing myocardial workload, coronary steal, angina, volume overload, and CRS needs further study in cardiac patients.

Persistent Postprandial Angina in a Patient With Gastroesophageal Reflux Disease: A Diagnostic Dilemma

Chest pain (CP) is a common reason for visits to the emergency department (ED). The underlying etiology of a good number of cases of CP can be diagnosed with adequate history taking and routine laboratory testing. However, atypical presentations of CP, in the settings of other causes of CP such as gastroesophageal reflux disease (GERD), can sometimes be tricky to diagnose with only routine lab tests and electrocardiogram (EKG). Herein, we present a 73-year-old male with a history of GERD and coronary artery disease who presented to our ED complaining of postprandial CP unaffected by exertion or rest. Initially, his symptoms were thought to be GERD-related but other heart-related causes of CP were considered due to the persistence of his CP postprandially. A cardiac stress test was subsequently done to rule out possible cardiac causes of his CP. His stress test was abnormal prompting heart catheterization that showed almost complete occlusion of his left anterior descending (LAD) and left circumflex (LCx) arteries. His symptoms resolved post-catheterization/stenting of his LAD and LCx arteries. He was later discharged unconditionally. His presentation highlights the required vigilance physicians must maintain when interrogating CP, even when other non-cardiac-related causes seem more plausible.

Possible further reduction in coronary flow velocity reserve in angina pectoris patients after oral glucose loading

BACKGROUND

Previous studies have suggested an increase in myocardial oxygen demand as a cause of postprandial angina. The purpose of this study was to assess coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD) before and after glucose ingestion in patients with known significant LAD stenosis.

METHODS

Fourteen patients with significant LAD stenosis and 20 subjects without LAD stenosis were enrolled. Transthoracic Doppler echocardiography was performed to measure the average peak diastolic coronary flow velocity (APDV) in the LAD at rest and during adenosine infusion. CFVR was calculated as APDV during adenosine infusion (APDVATP) divided by APDV at rest (APDVrest). APDVrest, APDVATP, and CFVR were assessed during fasting and 30, 60, and 120 min after a 75-g oral glucose loading.

RESULTS

In patients with LAD stenosis, APDVrest at 30 min after glucose loading was the highest at any time point. However, significant differences were not found in the APDVATP among time points in the patients or controls. Consequently, the CFVR in the patients was the lowest at 30 min after glucose loading (fasting, 1.77 ± 0.19; 30 min, 1.48 ± 0.16; 60 min, 1.69 ± 0.17; and 120 min, 1.76 ± 0.19; p < 0.01, ANOVA), as in the controls.

CONCLUSIONS

These findings suggested that the value of CFVR in the LAD was reduced after glucose loading. Myocardial risk area supplied by a stenosed coronary artery may be exposed to myocardial ischemia more frequently during oral glucose loading than during fasting in patients with significant coronary artery stenosis.

Efficacy and safety of controlled-release isosorbide-5-mononitrate in Japanese patients with stable effort angina pectoris

A new controlled-release isosorbide-5-mononitrate (CR-ISMN) preparation has been developed to meet the requirement for a low nitrate concentration interval in order to avoid nitrate tolerance. We conducted a randomized, double-blind, placebo-controlled study in 31 Japanese patients with stable effort angina pectoris to investigate the efficacy and safety of CR-ISMN. Patients were randomly assigned to either CR-ISMN (40 mg once daily) or placebo groups for 2 weeks after two consecutive symptom-limited treadmill exercise tests using the Bruce protocol to ascertain the reproducibility of exercise tolerance during the placebo run-in period. Exercise tests were repeated at 5, 12, and 24 hours after administration on the final day. No significant difference in exercise time to moderate angina was identified between the CR-ISMN and placebo groups at 5, 12, or 24 hours after administration. However, the changes in exercise were prolonged at 5 hours but not shortened at 24 hours in the CR-ISMN group. The results of subgroup analysis suggested that the concomitant use of insulin might lead to confounding results. Although headache was the most frequent adverse effect in the CR-ISMN group, all symptoms were mild and at self-limiting levels. The plasma concentrations of CR-ISMN maintained therapeutic levels at 5 and 12 hours, and gradually decreased to less than the minimum therapeutic concentration (100 ng/mL) at 24 hours after administration. This study demonstrates that CR-ISMN improves exercise tolerance during the daytime and is well-tolerated in Japanese patients with stable effort angina pectoris without increasing the number of serious adverse effects.

Assessment of Coronary Vasodilatation in Response to Nitroglycerin with Transthoracic Doppler Echocardiography

BACKGROUND

Previous studies demonstrated impaired coronary vasodilatory response (VR) to nitroglycerin (NG) in patients with coronary atherosclerosis. We hypothesized that the effect of the NG on the coronary blood flow (CBF) is negligible compared with its effect on the epicardial coronary artery dilatation and, therefore, that CBF velocity reduction after NG can reflect the magnitude of epicardial coronary artery dilatation.

METHODS

Quantitative coronary angiography was performed at the left anterior descending coronary artery (LAD) before and after intracoronary NG (200 mug) infusion in 18 patients with normal-looking coronary angiogram. VR assessed by quantitative coronary angiography (VRangio) was defined as: (LAD diameter after NG)(2)/(LAD diameter before NG)(2). Mean values measured at the ostium and at the junction of mid and distal LAD were used in the analysis. Diastolic CBF velocity was evaluated by using a 7-MHz transducer at the distal LAD before and 3 minutes after sublingual NG. VR assessed by echocardiography (VRecho) was defined as: (mean diastolic CBF velocity before sublingual NG)/(mean diastolic CBF velocity after sublingual NG). In 11 patients, plaque burden was assessed by intravascular ultrasound and results were compared with VRangio and VRecho.

RESULTS

VRecho was found to correlate well with VRangio (r = 0.71, P = .001), and VRangio and VRecho showed significant negative correlations with plaque burden (r = -0.66, P = .03; r = -0.77, P = .005, respectively).

CONCLUSIONS

VR to NG can be evaluated noninvasively with transthoracic Doppler echocardiography.

Coronary blood flow after cold exposure and the effect of warm-up exercise

BACKGROUND

Cold pressor test (CPT) results indicate that coronary blood flow (CBF) increases after sudden cold exposure. Traditionally, warm-up exercise (WEx) has been recommended before cold exposure; however, the physiologic effects of WEx on CBF have not been elucidated. Therefore, this study was undertaken to evaluate the effect of WEx on CBF after cold exposure.

METHODS

Fifteen healthy young men were enrolled in this study. CBF at the distal left anterior descending coronary artery was assessed by transthoracic Doppler echocardiography at baseline and after CPT. The same measurements were made with WEx and weight-bearing exercise before CPT after a 20-minute recovery period between each measurement. In the CBF velocities, the time-velocity integral of diastolic flow (Dtvi) was measured in addition to blood pressure and heart rate (HR).

RESULTS

The product of Dtvi x HR increased significantly after CPT. Increments in Dtvi x HR after CPT with WEx before CPT were significantly higher than CPT alone (130 +/- 82% vs 68 +/- 37%, P < .05). However, increments in Dtvi x HR after CPT with weight-bearing exercise before CPT were not significantly different from those observed for CPT alone (74 +/- 50% vs 68 +/- 37%, P = not significant).

CONCLUSION

Our study suggests that WEx can augment an increased CBF after cold exposure. This augmentation of CBF increase after cold exposure may help the body meet increased physiologic demands imposed on it by cold exposure. However, this phenomenon was not observed for anaerobic weight-bearing exercise.