Safety and feasibility of dobutamine and dipyridamole stress echocardiography in hypertensive patients

Evaluation of blood pressure response during dobutamine stress echocardiography in patients without cardiovascular diseases

Dobutamine stress echocardiography (DSE) is a diagnostic tool for determining coronary artery disease. Considering hypotension and hypertension as important complications of DSE, we aimed to evaluate the blood pressure (BP) responses during DSE. Patients without known cardiovascular diseases who underwent DSE were included. We excluded patients who had hypertension, diabetes mellitus, a known history of cardiovascular diseases, and those taking vasoactive medications. Systolic (SBP) and diastolic (DBP) blood pressure were recorded at baseline and peak stress. We included 688 patients with an age of 57.9 ± 12.01 years. During DSE, SBP (+19.72 ± 26.51 mm Hg, p < 0.001), DBP (+5.52 ± 17.35 mm Hg, p < 0.001), and HR (+54.05 ± 22.45 bpm, p < 0.001) significantly increased from baseline to peak stress. The normal cut-off value was measured between 101-210 mm Hg for SBP and 50-121 mm Hg for DBP. According to this normal cutoff, 11 (1.3%) and 30 (4.4%) patients had hypotensive and hypertensive SBP and 15 (2.2%) and 21 (3.1%) patients had hypotensive and hypertensive DBP, respectively. The hypotensive response was correlated with baseline SBP (r = 0.6, p = 0.001) and atropine (r = -2.18, p = 0.043), and the hypertensive response was correlated with baseline SBP (r = 0.048, p < 0.001). Baseline BP and atropine consumption were the independent variables associated with the outside-the-normal range of blood pressure responses.

Drug-Induced Atrial Fibrillation / Atrial Flutter

Drug-induced atrial fibrillation / flutter (DIAF) is a serious and potentially life-threatening complication of pharmacotherapy. Purpose of the work: systematization and analysis of scientific literature data on drugs, the use of which can cause the development of DIAF, as well as on epidemiology, pathophysiological mechanisms, risk factors, clinical picture, diagnosis and differential diagnosis, treatment and prevention of DIAF. Analysis of the literature has shown that many groups of drugs can cause the development of DIAF, with a greater frequency while taking anticancer drugs, drugs for the treatment of the cardiovascular, bronchopulmonary and central nervous systems. The mechanisms and main risk factors for the development of DIAF have not been finally established and are known only for certain drugs, therefore, this section requires further study. The main symptoms of DIAF are due to the severity of tachycardia and their influence on the parameters of central hemodynamics. For diagnosis, it is necessary to conduct an electrocardiogram (ECG) and Holter monitoring of an ECG and echocardiography. Differential diagnosis should be made with AF, which may be caused by other causes, as well as other rhythm and conduction disturbances. Successful treatment of DIAF is based on the principle of rapid recognition and immediate discontinuation of drugs (if possible), the use of which potentially caused the development of adverse drug reactions (ADR). The choice of management strategy: heart rate control or rhythm control, as well as the method of achievement (medication or non-medication), depends on the specific clinical situation. For the prevention of DIAF, it is necessary to instruct patients about possible symptoms and recommend self-monitoring of the pulse. It is important for practitioners to be wary of the risk of DIAF due to the variety of drugs that can potentially cause this ADR.

Layer-specific strain in dipyridamole stress echo: A new tool for the diagnosis of microvascular angina

BACKGROUND

Dipyridamole stress echocardiography (DSE) represents a fundamental test in patients with suspected coronary artery disease (CAD). The diagnosis of microvascular disease is still challenging. We aimed to determine the diagnostic value of left ventricular (LV) layer-specific longitudinal (LS) and circumferential strain (CS) by Speckle Tracking in detecting CAD during DSE and to study if they can help in discriminate between a negative echo and a suspected microvascular angina.

METHODS AND RESULTS

We enrolled 66 patients with known or suspected CAD. All underwent standard DSE. We identified 3 groups according to the result of DSE (36 negative DSE, 19 positive DSE, 11 indicatives for microvascular disease). Wall motion score index, global LV LS and CS (global longitudinal strain [GLS] and global circumferential strain [GCS]), and layer-specific LV LS and CS were measured at rest and peak stress. The Delta between rest and peak stress values was calculated. GLS increased after injection in negative DSE and microvascular disease while reducing in positive DSE. Endocardial GCS and transmural GCS values were stable in microvascular disease while increasing significantly in negative DSE, helping in the diagnosis. The specific analysis of endocardial LS showed the most powerful difference between healthy and macrovascular CAD patients, both for LS and CS.

CONCLUSIONS

Global circumferential strain can be a new valuable added tool in the echocardiographic diagnosis of microvascular disease. Endocardial GLS is the best indicator of an altered wall deformation in the presence of macrovascular ischemia.

Typical blood pressure response during dobutamine stress echocardiography of patients without known cardiovascular disease who have normal stress echocardiograms

AIMS

Blood pressure (BP) responses during dobutamine stress echocardiography (DSE) have not been systematically studied. Consequently, it is not known what constitutes a normal or an abnormal BP response to dobutamine stress. We sought to define the typical BP response during DSE of patients not known to have cardiovascular disease.

METHODS AND RESULTS

Of 24 134 patients who underwent DSE from November 2003 to December 2012 at Mayo Clinic, Rochester, MN, 2968 were selected for inclusion in this retrospective study. Excluded were patients with a history of hypertension, diabetes, or coronary artery disease, and those taking vasoactive medications. Patients who had baseline and/or stress-induced wall motion abnormalities were also excluded. The distribution of the study population's BP responses during DSE was Gaussian; we defined cut-point values for normative BP responses at 2 SD for each decade of age and for the whole study population. During DSE, systolic BP (SBP) increased from baseline to peak stress (Δ +2.9 ± 24 mmHg, P < 0.0001) and diastolic BP (DBP) decreased (Δ -7.4 ± 14 mmHg). BP changes were age and sex dependent; men and younger patients had greater ΔSBP and lesser ΔDBP, compared with women and older patients. Patients who received atropine had higher peak BP values than patients who did not receive atropine, due to greater ΔSBP (+7.4 ± 26 vs. -0.5 ± 22 mmHg, P < 0.0001) and lesser ΔDBP (-4 ± 14 vs. -9.7 ± 12 mmHg, P < 0.0001). This atropine effect was present in men and women, and was more pronounced in younger patients. The normative peak SBP values ranged from 82 to 182 mmHg.

CONCLUSION

BP responses during DSE vary and depend on patients' age, gender, and the use of atropine. We describe the typical BP responses seen during DSE and report normative reference values, which can be used for defining normal and abnormal BP responses to dobutamine stress.

Prediction of mortality by stress echocardiography in 2835 diabetic and 11 305 nondiabetic patients

BACKGROUND

To compare the capability by stress echocardiography results to predict overall mortality in a large unselected cohort of diabetic and nondiabetic patients.

METHODS AND RESULTS

The study group comprised 14 140 patients (2835 diabetics and 11 305 nondiabetics) who underwent stress echocardiography for evaluation of known (n=5671) or suspected (n=8469) coronary artery disease. Ischemia at stress echocardiography was observed in 768 (27%) diabetics and 2644 (23%) nondiabetics. During a median follow-up of 30 months (first quartile, 9; third quartile, 63), 1213 patients died. In diabetics, multivariable indicators of mortality were age (hazard ratio [HR], 1.07, 95% confidence interval [CI], 1.06-1.09), rest wall motion abnormality (HR, 2.43; 95% CI, 1.83-3.22), and ischemia at stress echocardiography (HR, 1.71; 95% CI, 1.34-2.18). In nondiabetics, multivariable indicators of mortality were age (HR, 1.07; 95% CI, 1.06-1.08), rest wall motion abnormality (HR, 2.19; 95% CI, 1.86-2.57), male sex (HR, 1.65; 95% CI, 1.41-1.93), ischemia at stress echocardiography (HR, 1.54; 95% CI, 1.32-1.80), and antischemic therapy at the time of test (HR, 1.15; 95% CI, 1.00-1.32). In stress echo negative subjects for ischemia, antischemic therapy showed increased annual mortality in nondiabetic patients with (3.8% versus 3.1%; P=0.04) or without rest wall motion abnormality (1.6% versus 0.9%; P<0.0001); it failed to do so in diabetic patients with (5.7% versus 5.8%; P=0.89) or without rest wall motion abnormality (2.6% versus 1.9%; P=0.10).

CONCLUSIONS

Ischemia at stress echocardiography is a strong and independent predictor of total mortality in diabetic as well as nondiabetic patients. Antischemic therapy markedly affects the negative predictive value of stress echocardiography in nondiabetic patients, whereas it is prognostically neutral in the diabetic population.

A phase I study on pharmacokinetics and pharmacodynamics of higenamine in healthy Chinese subjects

AIM

To investigate the pharmacokinetics, pharmacodynamics, and safety of higenamine, an active ingredient of Aconite root, in healthy Chinese volunteers.

METHODS

Ten subjects received continuous, intravenous infusion of higenamine at gradually escalating doses from 0.5 to 4.0 μg·kg(-1)·min(-1), each dose was given for 3 min. Blood and urine samples were collected at designated time points to measure the concentrations of higenamine. Pharmacodynamics was assessed by measuring the subject's heart rate. A nonlinear mixed-effect modeling approach, using the software Phoenix NLME, was used to model the plasma concentration-time profiles and heart rate.

RESULTS

Peak concentrations (C(max)) of higenamine ranged from 15.1 to 44.0 ng/mL. The half-life of higenamine was 0.133 h (range, 0.107-0.166 h), while the area under concentration-time curve (AUC), extrapolated to infinity, was 5.39 ng·h·mL(-1) (range, 3.2-6.8 ng·h·mL(-1)). The volume of distribution (V) was 48 L (range, 30.8-80.6 L). The total clearance (CL) was 249 L/h (range, 199-336 L/h). Within 8 h, 9.3% (range, 4.6%-12.4%) of higenamine was recovered in the urine. The pharmacokinetics of higenamine was successfully described using a two-compartment model with nonlinear clearance. In the pharmacodynamic model, heart rates were related to the plasma drug concentrations using a simple direct effect model with baseline. The E(0), E(max), and EC(50) were 68 bpm, 73 bpm and 8.1 μg/L, respectively.

CONCLUSION

Higenamine has desirable pharmacokinetic and pharmacodynamic characteristics. The results provide important information for future clinical studies on higenamine.

Advances in the cardiovascular assessment of patients with chronic kidney disease

Cardiovascular mortality is grossly elevated in patients with chronic kidney disease (CKD), and is associated with a wide variety of structural and functional abnormalities. These issues have driven additional attempts to further characterise these abnormalities to elucidate the pathophysiology involved, assess individual risk and/or target and monitor therapies specifically directed at the cardiovascular (CV) system. This review aims to assess the techniques that are currently available for the study of the CV system. This includes conventional assessments of the whole CV system from heart to peripheral microcirculation (although not deal with VC assessment), as well as the key functional consequences relating to stress induced cardiovascular reserve, perfusion and vasoregulation. In addition this review will introduce a variety of techniques aiming to expand the envelope of conventional measurements.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Clinical, resting echo and dipyridamole stress echocardiography findings for the screening of renal transplant candidates

BACKGROUND

Preoperative screening for coronary artery disease is recommended in high-risk renal transplant candidates. Aim of this study was to prospectively assess the value of a comprehensive risk stratification strategy including clinical, resting echo, and dipyridamole stress echo findings before renal transplantation.

METHODS

The study group consisted of 71 renal transplant candidates (47 men; age 54+/-11 years) fulfilling one or more of the following high-risk clinical criteria: history of coronary artery disease, wall motion abnormalities at resting echo, dialysis dependency lasting >5 years, presence of 2 or more risk factors. Clinical history, resting echo, and dipyridamole stress echo (up to 0.84 mg over 10 min + atropine up to 1 mg) were obtained in all subjects.

RESULTS

Mean number of risk factors was 2.5+/-1.0. Known coronary artery disease and diabetes were present, respectively, in 2 (3%) and 11 (15%) persons. No patient had left ventricular ejection fraction <45%. Left ventricular hypertrophy was found in 53 (74%) cases. Stress echo showed 100% safety and 97% overall feasibility. Inducible ischemia (new wall motion abnormalities) was detected in 3 (4%) subjects. During follow-up (36+/-12 months), 8 (11%) cardiac events occurred: 2 deaths, 2 myocardial infarctions, 3 coronary interventions, and 1 pulmonary edema. The perioperative period and subsequent follow-up (22+/-12 months) was uneventful among 32 patients who received renal transplantation. Four-year event-free survival was 92% in those without ischemia; it was 96% in the non-diabetic population. Diabetes (HR=4.78), age (HR=1.14), and left ventricular mass index (HR=1.02) were independent prognostic indicators among clinical and resting echo variables. The global chi-square of the statistical model was 18.8; it increased to 27.3 (+45%) after the addition of stress echo result.

CONCLUSIONS

Renal transplant candidates can undergo effective stratification of risk by combining clinical, resting echo and dipyridamole stress echo findings.

Anti-ischemic therapy and stress testing: pathophysiologic, diagnostic and prognostic implications

Anti-ischemic therapy, in particular beta-blockers, is the most commonly employed drug for the control of myocardial ischemia in patients with stable coronary artery disease. Its widespread use also in patients with suspected coronary artery disease has important practical, clinical diagnostic and prognostic implications because diagnostic tests are heavily influenced by its effects. In the present review, the pathophysiological mechanisms of ischemia protection by antianginal therapy are described. Not all stressors are created equal in front of the different classes of antianginal drugs and on their turn the different classes of drugs exert different levels of protection on inducible ischemia. Several clinical implications can be drawn: From the diagnostic viewpoint antianginal therapy decreases test sensitivity, offsetting the real ischemic burden for a too high percentage of false negative tests. From the prognostic viewpoint test positivity in medical therapy identifies a group of subjects at higher risk of experiencing cardiac death and positivity on medical therapy can be considered a parameter of ischemia severity. Nonetheless in patients with known coronary artery disease the ability of antianginal therapy to modify the ischemic threshold at stress testing represent a powerful means to assess therapy efficacy. From a practical viewpoint, the use of antianginal therapy at time of testing has advantages and disadvantages which are largely dependent on the purpose a test is performed: if the purpose of testing is to diagnose ischemia, it should be performed in the absence of antianginal medications. If the purpose of testing is to assess the protective effects of antianginal therapy, the test should be performed on medications.

Prediction of cardiac death in hypertensive patients with suspected or known coronary artery disease by stress technetium-99m tetrofosmin myocardial perfusion imaging

BACKGROUND

There are currently insufficient data to indicate a role for stress myocardial perfusion imaging as a prognostic tool in hypertensive patients.

OBJECTIVES

To assess the incremental value of stress myocardial perfusion imaging for the prediction of cardiac death in hypertensive patients relative to clinical data.

PATIENTS

We studied 601 hypertensive patients (aged 59 +/- 10 years, 387 men) who underwent exercise bicycle or dobutamine (up to 40 microg/kg per min) stress technetium-99m tetrofosmin single photon emission computed tomography (SPECT) for evaluation of coronary artery disease.

OUTCOME

Cardiac death during follow-up. RESULTS; An abnormal scan (reversible or fixed perfusion abnormalities) was detected in 293 (49%) patients (134 had reversible abnormalities). During a mean follow-up period of 3.1 +/- 1.3 years, 109 (18%) patients died; of whom, 42 patients (39%) died due to cardiac causes. Independent predictors of cardiac death were age [hazard ratio = 1.04, 95% confidence interval (CI) 1.01-1.08], history of previous myocardial infarction (hazard ratio = 2, CI 1.1-3.7), stress rate-pressure product (hazard ratio = 0.94, CI 0.87-0.98) and abnormal scan (hazard ratio = 4.7 CI 1.9-11.4). Both reversible and fixed abnormalities were predictive of death. The annual cardiac death rate was 5.3% in patients with an abnormal and 0.5% in patients with a normal perfusion scan.

CONCLUSION

Stress technetium-99m tetrofosmin myocardial perfusion imaging provides prognostic information incremental to clinical data for the prediction of cardiac death in hypertensive patients with known or suspected coronary artery disease.

Clinical, exercise electrocardiographic, and pharmacologic stress echocardiographic findings for risk stratification of hypertensive patients with chest pain

Exercise electrocardiography (ECG) is of limited usefulness in hypertensive patients, whereas pharmacologic stress echocardiography can provide diagnostic and prognostic information. The aim of this study was to compare the prognostic value of clinical data, exercise ECG, and pharmacologic stress echocardiography in hypertensive patients with chest pain and to identify the best strategy for their risk stratification. Three hundred sixty-seven hypertensive patients (189 men, age 61 +/- 9 years) with chest pain of unknown origin underwent exercise ECG and pharmacologic stress echocardiography (237 with dipyridamole and 130 with dobutamine) and were followed up for 31 +/- 24 months. Positive exercise ECG (ST-segment shift of > or =1 mm at 80 ms after the J point) and stress echocardiography (new wall motion abnormalities) were found in 130 (35%) and 86 (23%) patients, respectively. During follow-up, there were 13 deaths and 16 myocardial infarctions. Additionally, 43 patients underwent coronary revascularization and were censored accordingly. Of 12 clinical, electrocardiographic, and echocardiographic variables analyzed, a positive result of stress echocardiography was the only multivariate predictor of either death (hazard ratio [HR] 4.7, 95% confidence interval [CI] 1.5 to 14.5, p = 0.007) or hard events (death, myocardial infarction) (HR 4.1, 95% CI 1.8 to 9.3, p = 0.0009). Using an interactive stepwise procedure, stress echocardiography provided additional prognostic information to clinical evaluation and exercise ECG. However, the negative predictive value of the 2 tests was similarly (p = NS) high in assessing 4-year event-free survival. In conclusion, a negative exercise electrocardiographic test identifies low-risk hypertensive patients with chest pain and should be the first-line approach for risk stratification. In contrast, positive exercise ECG is unable to distinguish between patients with different levels of risk. In this case, stress echocardiography provides strong and incremental prognostic power over clinical and exercise electrocardiographic data.