Diagnostic value of stress echocardiography for the detection of restenosis after PTCA

Cardiorespiratory dynamics during respiratory maneuver in athletes

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation.

Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6 min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25 Hz).

Results: Performing a breathing maneuver at breathing 0.1 Hz and breathing 0.25 Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators–TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators–TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative.

Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Cardiorespiratory dynamics during respiratory maneuver in athletes

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation. Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6 min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25 Hz). Results: Performing a breathing maneuver at breathing 0.1 Hz and breathing 0.25 Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators-TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators-TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative. Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Usefulness of serial post-systolic shortening by speckle tracking echocardiography to predict major adverse cardiovascular events and segmental function improvement after acute myocardial infarction

Purpose

The aim is to determine whether serial post-systolic shortening (PSS) using speckle tracking echocardiography (STE) could predict major adverse cardiovascular events (MACE), especially symptom-driven infarct-related artery (IRA) revascularization and improvement in segmental function in post-myocardial infarction patients.

Methods/Results

Ninety-four patients (average age 61.1 ± 12.5 y, 84 [84.9%] male) with new-onset acute myocardial infarction were enrolled. Serial echocardiography was performed during the initial presentation, and at 3, 6 and 12 months after admission. PSS, strain and systolic strain rate were calculated using STE. Improvement in segmental function was defined as a decrease of ≧1 grade in wall motion score. During the follow-up (29.4 ± 12.7months), 22 patients (23.4%) had MACE and 17 patients had symptom-driven IRA revascularization. In multivariate model, PSS at 3 months was independently predictive for symptom-driven IRA revascularization (Hazard ratio (HR) = 0.5, 95% CI = 0.26–0.97) and for MACE (HR = 0.4, 95% CI = 0.24–0.67) (p < 0.05). Segmental function improvements were found in 255 segments (66.1%) and ROC curve analyses showed that AUC (95% CI) of the initial PSS was 0.7(0.65–0.77) (cut-off values = -1.08, sensitivity = 58%, specificity = 73% specificity).

Conclusions

Post-systolic shortening at 3 months is an independent predictor for symptom-driven IRA revascularization and MACE. Regional wall motion recovery also could be predicted by initial PSS. Serial assessment of two-dimensional STE should be investigated in post-myocardial infarction patients in the future.

Epicardial fat thickness correlates with coronary in-stent restenosis in patients with acute myocardial infarction

OBJECTIVE

To determine the relation between epicardial fat thickness and coronary in-stent restenosis in patients with acute myocardial infarction and percutaneous coronary intervention.

METHODS

A prospective study was conducted, which included 129 patients (67.3% male, mean age 62.9±10 years) with ST segment elevation acute myocardial infarction undergoing primary percutaneous coronary intervention with bare metal stent. Patients were divided in two groups according to the presence (n=21) or not (n=108) of in-stent restenosis during one year follow-up.

RESULTS

Epicardial fat was significantly thicker in patients with coronary in-stent restenosis (5.51±1.6 vs 4.14±2.0mm, p=0.006). A proportionally and significantly thicker epicardial fat was found according to the increase in coronary disease severity (3.3±0.9mm vs 4.3±1.8mm vs 4.7±2.3mm vs 6.7±2.2mm, for type A, B1, B2 and C lesions, respectively, p=0.001) and number of vessels (3.07±1.2mm vs 4.92±1.8mm vs 5.43±2.2mm, for one, two and three vessels disease, respectively, p<0.0001). Epicardial fat thickness ≥4.7mm had 75.0% sensibility and 69.0% specificity for predicting restenosis (AUC=0.737).

CONCLUSIONS

Echocardiographic evaluation of epicardial fat thickness could identify those patients with acute myocardial infarction with greater probabilities of in-stent restenosis after percutaneous coronary intervention.

The role of angiographic follow-up after percutaneous coronary intervention

In the early days of coronary angioplasty, follow-up coronary angiography was often performed to assess restenosis. Angiographic restenosis has been shown to be associated with worse clinical outcomes, though the exact causality has yet to be determined. Numerous studies have repeatedly demonstrated that routine follow-up coronary angiography increases the incidence of target lesion revascularization without a clear reduction in mortality or myocardial infarction. Despite the lack of proven benefit of angiographic follow-up, routine follow-up coronary angiography is still being performed in certain countries and facilities. There are several factors that might explain the lack of benefit of angiographic follow-up: 1) lower incidence of stent failure in the current drug-eluting stent era has attenuated the net clinical benefit of follow-up angiography. 2) Angiographic restenosis might not lead to myocardial ischemia. 3) Patients that do have functionally significant restenosis are often referred for coronary angiography due to clinical indications such as intractable angina. 4) Absence of restenosis at the time of follow-up angiography does not exclude future restenosis. The absence of proven benefit in unselected populations does not necessarily preclude the presence of benefit in selected population, and there may be a subgroup of patients who can benefit from angiographic follow-up such as those with a large myocardial ischemic territory or those at very high risk of restenosis. Until there is more clinical evidence with respect to follow-up angiography, the decision of whether or not to perform it routinely in selected high-risk population should entail an in-depth discussion with the patient.

Variations in the referral patterns to stress nuclear imaging and stress echocardiography scans

BACKGROUND

Stress myocardial perfusion imaging (MPI) and stress echocardiography (Echo) are commonly used for the noninvasive evaluation of patients with suspected coronary artery disease (CAD). Very few studies have compared the referral patterns to these imaging modalities in terms of the clinical profile of patients, reasons for referral, and type of referring physicians.

METHODS AND RESULTS

This was a prospective study of 1,020 consecutive patients who were referred for stress MPI (429 patients) or stress Echo (591 patients) at the American University of Beirut Medical Center in the year of 2008. Patients referred to MPI were older and had a higher prevalence of diabetes, hypertension, hypercholesterolemia, smoking, and previous myocardial infarction, coronary angioplasty, or bypass surgery. There were more abnormal scans in the stress MPI group (24% vs 15%, P < 0.001), as well as a higher prevalence of ischemia (15% vs 7.6%, P < 0.001) and impaired left ventricular function with an ejection fraction <50% (11% vs 1.7%, P < 0.001). A higher percentage of stress Echo studies were self-referred by physicians who themselves interpret the scans (31% vs 19%, P < 0.001).

CONCLUSION

Patients referred for stress MPI are at a higher risk than those referred for stress Echo having more CAD risk factors, more prior history of coronary events, and an older age. These findings have important implications in the interpretation of studies that compare the diagnostic and prognostic power of these two imaging modalities.

Usefulness of stress echocardiography for risk stratification of patients after percutaneous coronary intervention

The prognostic value of stress echocardiography in patients with previous percutaneous coronary intervention (PCI) remains undefined. The aim of this study was to investigate the prognostic implication of stress echocardiography after PCI. The study group comprised 1,063 patients (794 men, 65 +/- 10 years of age) who underwent stress echocardiography with exercise (n = 105), dipyridamole (n = 780), or dobutamine (n = 178) after a median of 10 months from a successful PCI. Of these patients, 616 (58%) complained of chest pain and 447 (42%) were asymptomatic. Stress echocardiogram was positive for inducible ischemia in 328 patients (31%). During a median follow-up of 20 months, there were 167 events (61 deaths, 106 infarctions). Independent predictors of mortality were age (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.03 to 1.09, p <0.0001), wall motion score index at rest (HR 3.91, 95% CI 2.19 to 6.99, p <0.0001), and ischemia at stress echocardiography (HR 1.82, 95% CI 1.05 to 3.16, p = 0.03). Five-year mortalities were 20% in patients with and 9% in those without ischemia (p = 0.006). Independent predictors of hard events were ischemia at stress echocardiography (HR 3.82, 95% CI 2.75 to 5.29, p <0.0001), age (HR 1.02, 95% CI 1.01 to 1.04, p = 0.009), wall motion score index at rest (HR 1.98, 95% CI 1.30 to 3.02, p = 0.002), multivessel disease at time of PCI (HR 1.45, 95% CI 1.05 to 2.02, p = 0.02), and female gender (HR 1.44, 95% CI 1.03 to 2.01, p = 0.03). Five-year hard event rates were 53% in patients with and 16% in those without ischemia (p <0.0001). Stress echocardiographic positivity added prognostic information to clinical and at-rest echocardiographic parameters in symptomatic and asymptomatic patients. Moreover, it identified a subset of patients at higher risk of developing hard events independent of the subtending coronary anatomy (multivessel or single vessel disease). In conclusion, stress echocardiography is effective in risk-stratifying patients with previous PCI. In particular, inducible ischemia is a strong and independent predictor of mortality and hard events.

Pacing stress echocardiography

Background

High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility.

Methods

The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG.

Conclusion

Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker.

The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an initial up- sloping followed by a later down-sloping trend, or flat or negative when peak stress pacing systolic pressure/end-systolic volume index is equal or lower than baseline stress values. This approach is certainly highly feasible and allows a conceptually immaculate definition of contractility with prognostic usefulness, but its therapeutic implications remains to be established. Bowditch treppe, assessed with pacing stress, can be used to assess the optimal stimulation frequency and to optimise the patient's chronotropic response in programming rate-adaptive pacemakers.