A comparison of the assessment and management of cardiometabolic risk in patients with and without type 2 diabetes mellitus in Canadian primary care.

AIM: To investigate the cardiometabolic risk (CMR) assessment and management patterns for individuals with and without type 2 diabetes mellitus (T2DM) in Canadian primary care practices. METHODS: Between April 2011 and March 2012, physicians from 9 primary care teams and 88 traditional non-team practices completed a practice assessment on the management of 2461 patients >40 years old with no clinical evidence of cardiovascular disease and diagnosed with at least one of the following risk factor-T2DM, dyslipidaemia or hypertension. RESULTS: There were 1304 individuals with T2DM and 1157 without. Pharmacotherapy to manage hyperglycaemia, dyslipidaemia and hypertension was widely prescribed. Fifty-eight percent of individuals with T2DM had a glycated haemoglobin (HbA1c) ≤7.0%. Amongst individuals with dyslipidaemia, median low-density lipoprotein cholesterol (LDL-C) was 1.8 mmol/l for those with T2DM and 2.8 mmol/l for those without. Amongst individuals with hypertension, 30% of those with T2DM achieved the <130/80 mmHg target, whereas 60% of those without met the <140/90 mmHg target. The composite glycaemic, LDL-C and blood pressure (BP) target outcome was achieved by 12% of individuals with T2DM. Only 17% of individuals with T2DM and 11% without were advised to increase their physical activity. Dietary modifications were recommended to 32 and 10% of those with and without T2DM, respectively. CONCLUSIONS: Patients at elevated CMR were suboptimally managed in the primary care practices surveyed. There was low attainment of recommended therapeutic glycaemic, lipid and BP targets. Advice on healthy lifestyle changes was infrequently dispensed, representing a missed opportunity to educate patients on the long-term benefits of lifestyle modification.

Poor achievement of guidelines-recommended targets in type 2 diabetes: findings from a contemporary prospective cohort study.

AIMS: To prospectively evaluate diabetes management in the primary care setting and explore factors related to guideline-recommended triple target achievement [blood pressure (BP) ≤ 130/80 mmHg, A1C ≤ 7% and low-density lipoprotein (LDL)-cholesterol < 2.5 mmol/l]. METHODS: Baseline, 6 and 12 month data on clinical and laboratory parameters were measured in 3002 patients with type 2 diabetes enrolled as part of a prospective quality enhancement research initiative in Canada. A generalised estimating equation model was fitted to assess variables associated with triple target achievement. RESULTS: At baseline, 54%, 53% and 64% of patients, respectively, had BP, A1C and LDL-cholesterol at target; all three goals were met by 19% of patients. The percentage of individuals achieving these targets significantly increased during the study [60%, 57%, 76% and 26%, respectively, at the final visit, p < 0.0001 except for A1C, p = 0.27]. A much smaller proportion of patients had adequate control during the entire study period [30%, 39%, 53% and 7%, respectively]. In multivariable analysis, women, patients younger than 65 years and patients of Afro-Canadian origin were less likely to achieve the triple target. DISCUSSION: As part of a quality enhancement research initiative, we observed important improvements in the attainment of guidelines-recommended targets in patients with type 2 diabetes followed for a 12-month period in the primary care setting; however, many individuals still failed to achieve and especially maintain optimal goals for therapy, particularly the triple target. Results of the multivariable analysis reinforce the need to address barriers to improve diabetes care, particularly in more susceptible groups.

Guidelines for the early management of acute coronary syndromes: focus on antithrombotic and antiplatelet therapy.

Despite important advances in the management of non-ST segment elevation acute coronary syndromes, adverse outcomes remain common. The recent introduction of low molecular weight heparins and platelet glycoprotein IIb/IIIa receptor inhibitors is an opportunity to make a further impact on the mortality and morbidity of this common condition. Optimal use of these agents will likely result from the recognition of patients at a higher risk of an adverse outcome who are most likely to benefit. At the same time, identification of lower risk patients will avoid the use of unnecessary and potentially harmful medications. Guidelines for the application of these new agents were developed at three meetings of a multidisciplinary group of health professionals. Evidence for risk stratification of patients with non-ST segment acute coronary syndromes and the results of clinical trials for the individual antithrombotic and antiplatelet agents were reviewed. A practical algorithm for patient management is presented, which uses observations available to the physician in the first few hours after the onset of chest pain.

Coding accuracy of hospital discharge data for elderly survivors of myocardial infarction.

OBJECTIVE: To assess the coding accuracy of primary and secondary discharge diagnoses in the Quebec hospital discharge database for elderly persons with myocardial infarction (MI). DESIGN: Retrospective chart review in a convenience sample of six Montreal hospitals. The diagnoses listed in the medical chart were compared with those listed in the hospital discharge database. For each subject, the Charlson comorbidity index was calculated twice, once based on the medical chart and again based on the hospital discharge database. PATIENTS: Subjects aged 65 years and over who had an MI coded as the primary discharge diagnosis in the hospital discharge database and who were discharged alive. MAIN RESULTS: For 234 MI survivors, the positive predictive value (ie, probability that a patient with MI reported in the hospital discharge database had an MI diagnosed by the discharging physician) for coding MI was 0.96 (95% CI 0.94, 0.98). Comorbid medical conditions and complications of the MI were under-reported in the hospital discharge database, which meant that the Charlson index based on the hospital discharge database was an average of 0.71 units lower than the Charlson index based on the medical chart. CONCLUSIONS: When studying survivors of MI by using hospital discharge databases, the advantages must be weighed against potential drawbacks in the quality of the information. Hospital discharge databases are almost as reliable as medical charts for identifying MI patients, but there is substantial under-reporting of comorbid medical conditions.

Maximal exercise testing for the selection of heart transplantation candidates: limitation of peak oxygen consumption.

BACKGROUND: Peak exercise oxygen consumption (peak VO2), which is considered an indicator of prognosis in advanced heart failure, is currently being used as a major criterion in many centers for the selection of candidates for heart transplantation. Available studies suggest that patients with peak VO2 < 14 mL/min/kg have improved survival and significant functional benefit with transplantation. Since patients may terminate symptom-limited exercise tests for a variety of reasons, peak VO2 does not necessarily reflect maximal VO2, leading to the possibility of inappropriate selection for transplantation. Therefore, we investigated the proportion of transplant candidates referred for exercise testing considered to have achieved maximal results from studies. METHODS: Fifty-five patients with heart failure, aged 51+/-9 years, (mean +/- SD) underwent maximum symptom-limited exercise tests on a cycle ergometer utilizing a Jones stage 1 incremental protocol. Tests were considered maximal if subjects achieved peak heart rate (HR) > 85% predicted ("cardiocirculatory limitation") or peak minute ventilation (VE) > 85% predicted ("ventilatory limitation"), and achieved an anaerobic threshold (AT) by noninvasive measures. RESULTS: Seven tests were terminated because of chest pain, ST-segment abnormalities, or ventricular arrhythmias. Of the remaining 48 studies, the reasons for stopping exercise were leg fatigue in 52%, dyspnea in 16%, and both symptoms in 23%. Sixteen of the 48 patients (33%) had peak VO2 < 14 mL/min/kg. In 8 of these 16 patients, both peak HR and VE were < 85% predicted. Of these eight without apparent HR or ventilatory limitation, none had oxygen desaturation below 90% or fall in BP, two were in atrial fibrillation, and only three had evidence that an AT was achieved. CONCLUSIONS: Among the patients with peak VO2 < 14 mL/min/kg, there were no objective signs of a cardiocirculatory or a respiratory limitation to exercise in half of them, and 31% did not achieve an AT either, thus not meeting any criteria to support evidence of maximal exercise. Exercise tests without objective evidence of cardiocirculatory or ventilatory limitation may not represent maximal performance. Consequently, peak VO2 may misclassify an appreciable proportion of candidates if the test results are submaximal. CLINICAL IMPLICATIONS: Clinical exercise studies indicating low peak VO2 must be interpreted in the context of whether a defined objective exercise limitation is evident to avoid biasing the selection of heart transplant candidates.

Cardiac versus noncardiac limits to exercise after heart transplantation.

BACKGROUND: To determine whether the reduced exercise capacity of patients after heart transplantation is primarily a result of decreased cardiac or peripheral vascular factors, we examined the cardiac output (CO) and right atrial pressure (Pra) relation during graded cycle ergometry. METHODS AND RESULTS: We studied 12 male patients (51.2+/-15.3 years [mean+/-SD]) 35.3+/-12.5 weeks after heart transplantation and 6 young healthy men. Patients had a normal increase in CO with increasing oxygen uptake (VO2) (CO = 0.00597 VO2 + 4.4, r = 0.83). Mean (+/-SEM) heart rate increased from 97.0+/-5.0 beats/min at rest to 146.9+/-6.9 beats/min at peak effort compared with the increase of 67.2+/-1.9 beats/min to 187.2+/-2.5 beats/min in the normal group. Pra in patients increased from 1.6+/-1.0 mm Hg at rest to 8.9+/-1.6 mm Hg during mild exercise but did not increase further at the highest work rates, even though CO continued to increase. In the normal group there was an initial increase in Pra from rest to exercise transition but little further change in Pra with increasing CO. Aerobic capacity (peak VO2) did not increase when cardiac function was increased with dobutamine during exercise in two patients. CONCLUSIONS: The steep increase in CO relative to Pra during severe exercise in patients who undergo heart transplantation argues against the heart as the sole limiting factor during maximal effort.

Efficacy and side-effects of cyclosporine dose monitoring with levels 6 h after the morning dose in heart transplant patients.

The purpose of this study was to compare CsA dose monitoring with trough levels (T0) vs. levels obtained 6 h after the morning dose of CsA (T6), with respect to the incidence of acute rejection and renal dysfunction, and the cumulative dose, as well as the cost of CsA after heart transplantation. Twenty consecutive adult heart transplant patients receiving quadruple sequential immunosuppression were prospectively randomized into CsA monitoring with T0 (Group I) vs. T6 levels (Group II). Oral CsA was started at a dosage of 2 mg/kg/d, 1-4 d after transplantation. The target range for either T0 or T6 was 150 to 250 ng/ml (enzyme multiplied immunologic technique), respectively. The CsA dose was increased or decreased by 0.5-1 mg/kg/d if the measured level was outside of the target range. Throughout the follow-up period (Group I, 11 +/- 2 months; Group II, 10 +/- 3 months), the incidence of acute rejection (ISHLT grade > or = 2) was 50% in each group. The left ventricular ejection fraction and serum creatinine were similar in both groups at 1 month and at the end of the follow-up. The maximal dose of CsA (mg/kg/d): 3.8 +/- 1 vs. 5 +/- 0.6 (P = 0.002), the minimal dose: 2.2 +/- 0.7 vs. 3.4 +/- 0.8 (P = 0.003), and the current dose: 2.6 +/- 0.6 vs. 3.5 +/- 1 (P = 0.02), were lower in Group II, as well as the cumulative dose of CsA (mg): 61,790 +/- 19,754 vs. 88,524 +/- 18,082 (P = 0.005), and its cost (CDN$): 3,589 +/- 1,116 vs. 5,106 +/- 1,045 (P = 0.005). In conclusion, CsA dose monitoring with T6 was associated with a 30% lower CsA dose and cost compared to T0, with the same effectiveness in the prevention of acute rejection, and similar cardiac and renal function.

Hill's sign in aortic regurgitation: enhanced pressure wave transmission or artefact?

BACKGROUND: Hill's sign (an exaggerated difference in systolic arterial pressure between upper and lower limbs) is described in current textbooks of cardiology as an indicator of the severity of aortic insufficiency. OBJECTIVE: To evaluate the clinical value of Hill's sign in the assessment of aortic insufficiency. A further aim was to review arterial pressure transmission in health and disease to indicate whether aortic insufficiency might be associated with abnormalities of pressure wave transmission. DESIGN: Observational study of central and peripheral arterial hemodynamics from five patients with severe aortic insufficiency compared with sphygmomanometrically recorded upper and lower limb pressures. SETTING: Diagnostic cardiac catheterization laboratory. MAIN RESULTS: In five patients with proven severe aortic insufficiency, intra-arterial pressure measurements did not demonstrate any exaggerated difference in systolic pressure between either aortic and femoral or axillary and femoral arteries. Noninvasive sphygmomanometric pressures in the upper limb correlated well with axillary arterial recordings. However, lower limb noninvasive measurements gave systolic pressures well above the intraarterial recording, and in three patients the Korotkoff sounds over the popliteal artery could not be eliminated by high thigh cuff pressures. CONCLUSIONS: A review of publications of arterial pressure transmission in health and disease does not indicate any physiological basis for Hill's sign. Therefore, on the basis of the present observations it is concluded that Hill's sign is an artefact of sphygmomanometric lower limb pressure measurement, has no physiological basis, and appears to be absent in some patients with severe aortic insufficiency. Hill's sign should, therefore, be removed from the list of diagnostic signs for aortic insufficiency.

An integrated approach to the surgical management of heart failure.

Many among the large and increasing number of patients suffering from heart failure can benefit from surgical interventions. The indications, efficacy and limitations of various surgical procedures currently available are reviewed, and an integrated approach to offer surgical therapy optimal for the particular patients is proposed.

Time varying loading of the pulmonary circulation: a model to describe hemodynamic observations in the stiff left atrial syndrome.

OBJECTIVE: To develop a mathematical model that could explain the following observations: that right heart failure can develop in association with no other cardiac abnormality than a severe reduction in the compliance of the left atrium; and that patients with this syndrome have systolic pulmonary hypertension with left atrial v waves in the absence of either mitral regurgitation or left ventricular dysfunction. DESIGN: A model of the pulmonary circulation was designed with a time varying terminal hydraulic load, which was varied between a noncompliant left atrium during systole and a compliant left ventricle/left atrium combination during diastole. Using representative parameters and a pulmonary arterial flow wave as input, pressures in the pulmonary artery and left atrium and right ventricular power output were calculated. RESULTS: Pulmonary arterial and left atrial systolic pressures are increased as left atrial compliance is reduced. The time varying change in terminal load results in an increase in systolic pressures, whereas diastolic pressures remain normal. A decrease in left atrial compliance increases both the nonpulsatile and pulsatile components of pulmonary input impedance, whereas only the nonpulsatile component of right ventricular power output is increased. CONCLUSIONS: The time varying pulmonary load model of the pulmonary circulation, in the presence of a reduced left atrial compliance results in pulmonary, and left atrial pressures similar to those observed in patients with the stiff left atrial syndrome. The resulting increase in right ventricular power output could be an important factor in the development of right heart failure.

Aortofemoral transfer function: a method to determine the instantaneous aortic valve gradient in aortic valve stenosis.

OBJECTIVES: This study was performed to evaluate the use of synthesized ascending aorta pressure, calculated from femoral artery pressure using an aortofemoral transfer function, in the assessment of aortic valve stenosis. BACKGROUND: Measurement of an accurate aortic valve gradient in patients with aortic stenosis often requires simultaneous recordings of ascending aorta and left ventricular pressures. The use of femoral artery pressure is considered to be a poor substitute for ascending aorta pressure. However, the aortic pressure wave can be calculated from the femoral artery pressure if the aortofemoral transfer function has been determined. METHOD: Femoral artery pressure from the side arm of an introducer sheath and ascending aorta pressure are recorded simultaneously and the data stored in a personal computer. An aortofemoral transfer function is determined from the ratio of the Fourier components of aortic and femoral pressures. Left ventricular and femoral artery pressures are then recorded. Using the previously determined transfer function, the simultaneous ascending aorta pressure is calculated from the femoral pressure. RESULTS: Ascending aorta pressure waveforms estimated from femoral artery pressure closely resembled the simultaneously recorded ascending aorta pressure. Mean aortic valve gradients calculated from the synthesized aortic pressure correlated well with the gradient measured from direct recordings of aortic pressure (r = 0.98). There was also a good relation between valve areas (r = 0.93) and valve resistances (r = 0.98) calculated using the two methods. CONCLUSIONS: Using current computer technology, accurate aortic valve gradients can be rapidly calculated using femoral artery pressure as a substitute for ascending aorta pressure. This technique will reduce the need and risks of multiple catheters to determine aortic valve gradients.

A method of dynamic analysis of iodine-123-metaiodobenzylguanidine scintigrams in cardiac mechanical overload hypertrophy and failure.

Cardiac sympathetic neuronal degeneration accompanies mechanical overload heart failure. We hypothesized that sympathetic nerve and myocyte failure share a common etiology and that 123I-metaiodobenzylguanidine (MIBG) might provide a precise method of detecting failure in chronic mechanical overload. Our aim was to develop a method for the dynamic analysis of 123I-MIBG scintigrams which could yield a quantitative index of myocardial sympathetic neuronal function in this condition. We performed serial 123I-MIBG scintigraphy in 33 volunteers, 10 orthotopic cardiac transplant recipients and 26 patients with chronic mechanical overload of the left ventricle. We constructed a compartmental model in which total heart activity represents the sum of cardiac sympathetic vesicular and cytosolic pools. Patients with antecedent mechanical overload heart failure or myocardial dysfunction had accelerated myocardial egress of tracer that we ascribed to a specific impairment in vesicular storage rather than to a more rapid turnover of an intact vesicular pool.

Noninvasive determination of aortic input impedance and external left ventricular power output: a validation and repeatability study of a new technique.

OBJECTIVE: The study was designed to test whether aortic input impedance and left ventricular power output can be accurately assessed noninvasively. BACKGROUND: Aortic input impedance describes both the pulsatile and nonpulsatile artery load encountered by the left ventricle. Until now, this measure of afterload has only been determined by invasive techniques. METHODS: The aortic pressure wave was estimated by recording the calibrated carotid artery pressure wave noninvasively with use of a micromanometer-tipped probe by the technique of applanation tonometry. Flow was determined with pulsed wave Doppler measurement of ascending aortic velocity profile and aortic diameter. In 18 subjects undergoing cardiac catheterization, invasive measurements were taken to assess the accuracy of noninvasive data. In 17 other subjects noninvasive measurements were taken on different days to assess the reproducibility of results. RESULTS: Noninvasive pressure measurements correlated well with invasive data: systolic pressure (mm Hg), noninvasive 126 +/- 28 versus invasive 127 +/- 28, r = 0.96, p less than 0.001; diastolic pressure (mm Hg), noninvasive 71 +/- 10 versus invasive 66 +/- 7, r = 0.60, p less than 0.02; augmentation index (%), noninvasive 23.9 +/- 9.3 versus invasive 30.7 +/- 11.9, r = 0.87, p less than 0.001. Doppler-measured cardiac output was closely correlated with invasively measured flow (liters/min): Doppler, 5.3 +/- 1.2 versus invasive, 5.5 +/- 1.3, r = 0.98, p less than 0.001. Impedance and left ventricular power variables calculated from noninvasive and invasive techniques were also closely related: systemic vascular resistance (dynes.s.cm-5), noninvasive 1,479 +/- 488 versus invasive 1,502 +/- 498, r = 0.91, p less than 0.001; characteristic impedance (dynes.s.cm-5), noninvasive 137 +/- 52 versus invasive 136 +/- 79, r = 0.92, p less than 0.001; pulsatile power (mW), noninvasive 249 +/- 94 versus invasive 291 +/- 103, r = 0.91, p less than 0.001; mean power (mW), noninvasive 1,107 +/- 319 versus invasive 1,144 +/- 266, r = 0.93, p less than 0.001. Repeated measures of impedance variables and power output showed coefficients of variation of less than 9%. CONCLUSIONS: Measurement of noninvasive impedance by this technique provides an accurate and repeatable assessment of mean and pulsatile cardiac load.

LV-arterial coupling: interactive model to predict effect of wave reflections on LV energetics.

The interaction between the left ventricle (LV) and the arterial system was simulated using sequential convolution of the flow output generated by a time-varying elastance model of the LV with an impulse response calculated from a 128-element model of the arterial system. The model illustrates the effect of independent changes of components of the arterial load on LV performance and energetics. This report studies the response of the model LV to an increase in arterial resistance, a decrease in arterial compliance, and an increase in discrete vascular reflections. Although arterial resistance exerts the greatest effect on ventricular stroke output, a reduction of arterial compliance or an increase in early reflections resulted in less optimal coupling of the heart to the arteries and less efficient energy utilization by the LV. In addition, the earlier the reflections return, the greater the disturbance of ventricular arterial coupling.