Relation between diastolic left ventricular function and myocardial blood volume during adenosine-induced coronary hyperemia

An acute increase in Left Atrial volume and left ventricular filling pressure during Adenosine administered myocardial hyperaemia: CMR First-Pass Perfusion Study

OBJECTIVE

To investigate whether left atrial (LA) volume and left ventricular filling pressure (LVFP) assessed by cardiovascular magnetic resonance (CMR) change during adenosine delivered myocardial hyperaemia as part of a first-pass stress perfusion study.

METHODS AND RESULTS

We enrolled 33 patients who had stress CMR. These patients had a baseline four-chamber cine and stress four-chamber cine, which was done at peak myocardial hyperaemic state after administering adenosine. The left and right atria were segmented in the end ventricular diastolic and systolic phases. Short-axis cine stack was segmented for ventricular functional assessment. At peak hyperaemic state, left atrial end ventricular systolic volume just before mitral valve opening increased significantly from baseline in all (91 ± 35ml vs. 81 ± 33ml, P = 0.0002), in males only (99 ± 35ml vs. 88 ± 33ml, P = 0.002) and females only (70 ± 26ml vs. 62 ± 22ml, P = 0.02). The right atrial end ventricular systolic volume increased less significantly from baseline (68 ± 21ml vs. 63 ± 20ml, P = 0.0448). CMR-derived LVFP (equivalent to pulmonary capillary wedge pressure) increased significantly at the peak hyperaemic state in all (15.1 ± 2.9mmHg vs. 14.4 ± 2.8mmHg, P = 0.0002), females only (12.9 ± 2.1mmHg vs. 12.3 ± 1.9mmHg, P = 0.029) and males only (15.9 ± 2.8mmHg vs. 15.2 ± 2.7mmHg, P = 0.002) cohorts.

CONCLUSION

Left atrial volume assessment by CMR can measure acute and dynamic changes in preloading conditions on the left ventricle. During adenosine administered first-pass perfusion CMR, left atrial volume and LVFP rise significantly.

Temporal analysis of regional strain rate during adenosine triphosphate stress before and after percutaneous coronary interventions

Regional myocardial ischemia is thought to be characterized by diastolic dysfunction. We aimed to clarify whether temporal analysis of strain rate (SR) index derived from two-dimensional speckle-tracking echocardiography (2DTE) can assess the regional myocardial ischemia or not. Forty-two patients with significant coronary stenoses were referred for percutaneous coronary intervention (PCI). 2DTE was performed before and a day after PCI. Time from aortic valve closure to peak early diastolic longitudinal SR ∆(TAVC-E SR) was measured both at baseline and during adenosine triphosphate (ATP) infusion. TAVC-E SR was calculated as TAVC-E SR during ATP infusion subtracted by TAVC-E SR at baseline. In forty-five target ischemic regions, TAVC-E SR at baseline was significantly longer than that of control regions (166 ± 28 vs. 136 ± 32 ms, P < 0.0001). TAVC-E SR in target ischemic regions significantly prolonged during ATP stress to 221 ± 37 ms (P < 0.0001), while it did not change in control regions. Immediately after PCI, TAVC-E SR in target regions significantly decreased to 135 ± 27 ms, P < 0.0001 without prolongation during ATP stress. Receiver operating characteristic curves demonstrated that ∆TAVC-E SR could assess regional myocardial ischemia by a cutoff criterion of 14 ms with sensitivity of 93% and specificity of 95%. 2DTE-derived TAVC-E SR significantly increased during ATP stress only in ischemic myocardium. This phenomenon disappeared immediately after PCI. Temporal analysis of TAVC-E SR appeared to be useful to assess the regional myocardial ischemia.

Left ventricular hypertrophy in hypertension as a predictor of coronary events: relation to geometry

The present review examines epidemiological evidence for a relation of left ventricular hypertrophy with coronary heart disease, and mechanisms that may represent pathophysiological links between left ventricular hypertrophy and coronary events. Left ventricular hypertrophy has been demonstrated to be a powerful predictor of coronary heart disease, and when geometry is concentric the relation is even stronger. In addition to its association with risk factors for atherosclerosis and mechanisms that precipitate acute heart attacks, left ventricular hypertrophy also directly predisposes to and aggravates clinical presentation of coronary heart disease through a number of biological mechanisms. These include the following: increase in oxygen requirement related to left ventricular geometry; coronary hypertension, with endothelial dysfunction and reduced coronary reserve; diastolic dysfunction; and structural remodelling of myocardium and vascular bed. Some of these alterations are also worsened by underlying coronary heart disease, and can potentially be maintained by loop mechanisms. A recognizable stage of abnormal coronary haemodynamics in the context of left ventricular hypertrophy is probably that at which coronary reserve is impaired in the absence of any other sign of heart disease; in many circumstances, this may occur early in the disease process.

Correlation between hemodynamic changes and tomographic sestamibi imaging during dipyridamole-induced coronary hyperemia

OBJECTIVES

The purposes of this study were to examine the effects of dipyridamole infusion on hemodynamic variables and to compare these changes with myocardial perfusion.

BACKGROUND

Dipyridamole stress testing with myocardial perfusion imaging is widely used in the assessment of patients with known or suspected coronary artery disease (CAD). Few studies, however, have correlated the hemodynamic effects of dipyridamole using invasive monitoring with perfusion patterns in patients with chest pain syndromes.

METHODS

Hemodynamic measurements were made in the cardiac catheterization laboratory with a Swan-Ganz thermodilution catheter before, during and after infusion of dipyridamole (142 microg/kg body weight per min for 4 min). Technetium-99m sestamibi was injected 3 min after the completion of the infusion.

RESULTS

There were 20 patients with and 6 without CAD, as demonstrated by angiography. Compared with baseline values, dipyridamole resulted in an increase in pulmonary capillary wedge pressure (54 +/- 78% vs. 32 +/- 26%, p = NS), cardiac index (36 +/- 21% vs. 40 +/- 18%, p = NS) and stroke volume index (16 +/- 18% vs. 40 +/- 18%, p = NS) and a decrease in systemic vascular resistance (22 +/- 13% vs. 24 +/- 11%, p = NS), aortic pressure (2 +/- 9% vs. 0 +/- 6%, p = NS) and pulmonary vascular resistance (19 +/- 25% vs. 11 +/- 32%, p = NS) in patients with and without CAD. The peak effect of dipyridamole on heart rate, systemic vascular resistance and pulmonary capillary wedge pressure was evident at 3 min after infusion in 70% of patients. Aminophylline, given to 20 patients, improved hemodynamic variables within 2 min. The single-photon emission computed tomographic sestamibi images were normal in the 6 patients without and abnormal in the 18 patients with CAD.

CONCLUSIONS

Dipyridamole-induced coronary hyperemia produces mild hemodynamic changes in patients with and without CAD; these changes are at or near peak effect at 3 min after infusion and are rapidly reversed by aminophylline.

Results of adenosine single photon emission computed tomography thallium-201 imaging in hemodynamic nonresponders

Systolic blood pressure typically decreases during adenosine infusion because of stimulation of A2b receptors, resulting in systemic vasodilation. This study examined the results of adenosine single photon emission computed tomography (SPECT) thallium-201 imaging in patients who did not show such a decrease in blood pressure during peak adenosine effect (nonresponders). The 102 nonresponders and 341 responders had no significant differences in age, gender, history of diabetes mellitus, hypertension, or previous myocardial infarction. The extent of coronary artery disease (CAD) by angiography was also similar. The sensitivity of SPECT thallium-201 imaging in patients with one-vessel disease was 82% in nonresponders and 84% in responders (p value not significant [NS]); in patients with multivessel disease, it was 90% in nonresponders and 94% in responders (p = NS) and for all CAD, it was 87% in non-responders and 91% in responders (p = NS). Thus lack of hemodynamic systemic response during adenosine infusion does not affect sensitivity for detecting CAD.