Impact of a cuff-based device calibration method on the agreement between invasive and noninvasive aortic and brachial pressure.

INTRODUCTION: Brachial cuff-based methods are increasingly used to estimate aortic systolic blood pressure (aoSBP). However, there are several unresolved issues. AIMS: to determine to what extent the scheme used to calibrate brachial records (1) can affect noninvasive obtained aoSBP levels, and consequently, the level of agreement with the aoSBP recorded invasively, and (2) how different ways of calibrating ultimately impact the relationship between aoSBP and cardiac properties. METHODS: brachial and aortic blood pressure (BP) was simultaneously obtained by invasive (catheterisation) and noninvasive (brachial oscillometric-device) methods (89 subjects). aoSBP was noninvasive obtained using three calibration schemes: 'SD': diastolic and systolic brachial BP, 'C': diastolic and calculated brachial mean BP (bMBP), 'Osc': diastolic and oscillometry-derived bMBP. Agreement between invasive and noninvasive aoSBP, and associations between BP and echocardiographic-derived parameters were analysed. CONCLUSIONS: 'C' and 'SD' schemes generated aoSBP levels lower than those recorded invasively (mean errors: 6.9 and 10.1 mmHg); the opposite was found when considering 'Osc'(mean error: -11.4 mmHg). As individuals had higher invasive aoSBP, the three calibration schemes increasingly underestimated aoSBP levels; and viceversa. The 'range' of invasive aoSBP in which the calibration schemes reach the lowest error level (-5-5 mmHg) is different: 'C': 103-131 mmHg; 'Osc': 159-201 mmHg; 'SD':101-124 mmHg. The calibration methods allowed reaching levels of association between aoSBP and cardiac characteristics, somewhat lower, but very similar to those obtained when considering invasive aoSBP. There is no evidence of a clear superiority of one calibration method over another when considering the association between aoSBP and cardiac characteristics.

Quality improvement collaborative to optimize heart failure care in patients from a network of clinics in Argentina during the COVID-19 pandemic.

Heart failure (HF) is a major clinical and public health problem associated with significant mortality, morbidity, and health-care costs. Despite the existence of evidence-based guidelines for the optimal treatment of HF, the quality of care remains suboptimal. Our aim was to increase the use a care bundle in 50% of enrolled subjects during their hospitalization and discharge and to reduce their readmission for HF causes by 10%. We conducted an uncontrolled before-after study in eight hospitals in Argentina to evaluate the effect of a quality improvement intervention on the use of an HF care bundle in patients with HF New York Heart Association (NYHA) Class II-III. The HF bundle of care included medication, continuum of care, lifestyle habits, and predischarge examinations. Training and follow-up of multidisciplinary teams in each center were performed through learning sessions and plan-do-study-act improvement cycles. Data collectors reviewed bundle compliance in the health records of recruited patients after their hospital discharge and verified readmissions through phone calls to patients within 30-40 days after discharge. We recruited 200 patients (83 before and 127 during the intervention phase), and bundle compliance increased from 9.6% to 28.3% [odds ratio 3.71, 95% confidence interval (8.46; 1.63); P = .002]. Despite a slow improvement during the first months, bundle compliance gained momentum near the end of the intervention surpassing 80%. We observed a non-significant decreased readmission rate within 30 days of discharge due to HF in the postintervention period [8.4% vs. 5.5%, odds ratio 0.63, 95% CI (1.88; 0.21); P = .410]. Qualitative analysis showed that members of the intervention teams acknowledged the improvement of work organization and standardization of care, teamwork, shared mental model, and health record completeness as well as the utility of training fellows. Despite the challenges related to the pandemic, better care of patients with HF NYHA Class II-III was possible through simple interventions and collaborative work. Graphical abstract.

Direct estimation of central aortic pressure from measured or quantified mean and diastolic brachial blood pressure: agreement with invasive records.

Background: Recently it has been proposed a new approach to estimate aortic systolic blood pressure (aoSBP) without the need for specific devices, operator-dependent techniques and/or complex wave propagation models/algorithms. The approach proposes aoSBP can be quantified from brachial diastolic and mean blood pressure (bDBP, bMBP) as: aoSBP = bMBP2/bDBP. It remains to be assessed to what extent the method and/or equation used to obtain the bMBP levels considered in aoSBP calculation may affect the estimated aoSBP, and consequently the agreement with aoSBP invasively recorded. Methods: Brachial and aortic pressure were simultaneously obtained invasively (catheterization) and non-invasively (brachial oscillometry) in 89 subjects. aoSBP was quantified in seven different ways, using measured (oscillometry-derived) and calculated (six equations) mean blood pressure (MBP) levels. The agreement between invasive and estimated aoSBP was analyzed (Concordance correlation coefficient; Bland-Altman Test). Conclusions: The ability of the equation "aoSBP = MBP2/DBP" to (accurately) estimate (error <5 mmHg) invasive aoSBP depends on the method and equation considered to determine bMBP, and on the aoSBP levels (proportional error). Oscillometric bMBP and/or approaches that consider adjustments for heart rate or a form factor ∼40% (instead of the usual 33%) would be the best way to obtain the bMBP levels to be used to calculate aoSBP.

Improvement in coronary endothelial function is independently associated with a slowed progression of coronary artery calcification in type 2 diabetes mellitus.

AIMS: To examine a relationship between alterations of structure and function of the arterial wall in response to glucose-lowering therapy in type 2 diabetes mellitus (DM) after a 1-year follow-up (FU). METHODS AND RESULTS: In DM (n = 22) and in healthy controls (n = 17), coronary artery calcification (CAC) was assessed with electron beam tomography and carotid intima-media thickness (IMT) with ultrasound, whereas coronary function was determined with positron emission tomography-measured myocardial blood flow (MBF) at rest, during cold pressor testing (CPT), and during adenosine stimulation at baseline and after FU. The decrease in plasma glucose in DM after a mean FU of 14 +/- 1.9 months correlated with a lower progression of CAC and carotid IMT (r = 0.48, P < or = 0.036 and r = 0.46, P < or = 0.055) and with an improvement in endothelium-related DeltaMBF to CPT and to adenosine (r = 0.46, P < or = 0.038 and r = 0.36, P < or = 0.056). After adjusting for metabolic parameters by multivariate analysis, the increases in DeltaMBF to CPT after glucose-lowering treatment remained a statistically significant independent predictor of the progression of CAC (P < or = 0.001 by one-way analysis of variance). CONCLUSION: In DM, glucose-lowering treatment may beneficially affect structure and function of the vascular wall, whereas the observed improvement in endothelium-related coronary artery function may also mediate direct preventive effects on the progression of CAC.

Structural alterations of the coronary arterial wall are associated with myocardial flow heterogeneity in type 2 diabetes mellitus.

PURPOSE: To determine the relationship between carotid intima-media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM). METHODS: In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined with electron beam tomography (EBT). Global and regional MBF was determined in milliliters per gram per minute with (13)N-ammonia and positron emission tomography (PET) at rest, during cold pressor testing (CPT), and during adenosine (ADO) stimulation. RESULTS: There was neither a relationship between carotid IMT and CAC (r = 0.10, p = 0.32) nor between carotid IMT and coronary circulatory function in response to CPT and during ADO (r = -0.18, p = 0.25 and r = 0.10, p = 0.54, respectively). In 33 individuals, EBT detected CAC with a mean Agatston-derived calcium score of 44 +/- 18. There was a significant difference in regional MBFs between territories with and without CAC at rest and during ADO-stimulated hyperemia (0.69 +/- 0.24 vs. 0.74 +/- 0.23 and 1.82 +/- 0.50 vs. 1.95 +/- 0.51 ml/g/min; p < or = 0.05, respectively) and also during CPT in DM but less pronounced (0.81 +/- 0.24 vs. 0.83 +/- 0.23 ml/g/min; p = ns). The increase in CAC was paralleled with a progressive regional decrease in resting as well as in CPT- and ADO-related MBFs (r = -0.36, p < or = 0.014; r = -0.46, p < or = 0.007; and r = -0.33, p < or = 0.041, respectively). CONCLUSIONS: The absence of any correlation between carotid IMT and coronary circulatory function in type 2 DM suggests different features and stages of early atherosclerosis in the peripheral and coronary circulation. PET-measured MBF heterogeneity at rest and during vasomotor stress may reflect downstream fluid dynamic effects of coronary artery disease (CAD)-related early structural alterations of the arterial wall.

Predictors of aorto-saphenous vein bypass narrowing late after coronary artery bypass grafting.

The objective of this study was to evaluate the clinical and angiographic factors associated with significant saphenous vein graft (SVG) atherosclerosis progression at mid-term follow-up in a series of unselected coronary patients who had previously received a coronary artery bypass graft (CABG). A total of 123 SVGs from 86 patients who underwent cardiac catheterization twice, 15 +/- 12 months apart, were included in the study. None of the SVGs presented any > or =50% diameter stenosis (DS) lesion or underwent any intervention at baseline. All SVGs were divided into 3 segments and each SVG segment was scored from 0 to 3 depending on the presence of lesions, with percent DS ranging from 0% to 19% (score 0), 20% to 29% (score 1), 30% to 39% (score 2), and > or =40% (score 3). The SVG atherosclerotic burden score (ABS) was calculated by adding the score obtained for each of the 3 SVG segments. Significant progression was defined as > or =10% increase in lesion percent DS or > or =0.6 mm decrease in minimal lumen diameter between baseline and follow-up studies. Mean age of the study population was 66 +/- 9 years, and most of the patients were receiving statin therapy with mean low-density lipoprotein cholesterol of 85 +/- 26 mg/dl. Significant angiographic progression occurred in > or =1 SVG in 41 patients (48%). On multivariate analysis, the variables associated with SVG atherosclerosis progression were SVG ABS (odds ratio [OR], 1.52 for each increase of 1 point in SVG ABS; 95% confidence interval [CI] 1.1 to 2.29) and high-density lipoprotein (HDL) cholesterol (OR 1.38 for each decrease of 5 mg/dl in HDL cholesterol levels, 95% CI 1.09 to 1.85). Twenty-two patients (26%) had a cardiac event at follow-up related to SVG disease progression. The percent DS of the SVG segment at baseline was associated with SVG disease progression leading to a cardiac event (OR 3.67 for each increase of 5% in percent DS, 95% CI 2.11 to 6.38). In conclusion, simple clinical and angiographic variables such as HDL cholesterol, ABS, and lesion severity remain independent predictors of significant SVG atherosclerosis progression in mild to moderately diseased SVGs despite mean low-density lipoprotein levels <90 mg/dl.

Determinants of myocardial blood flow response to cold pressor testing and pharmacologic vasodilation in healthy humans.

PURPOSE: Response of myocardial blood flow (MBF) to sympathetic stimulation with cold is modulated by endothelium-related factors and is typically altered in the presence of coronary risk factors. Determinants of flow response to cold pressor testing (CPT) in normal volunteers at low risk for CAD remain less well defined, especially relative to baseline conditions such as hemodynamics and MBF, plasma substrate and lipid levels, and total pharmacologically stimulated vasodilator capacity. METHODS: In 50 normal volunteers (42+/-13 years; 31 women) without coronary risk factors, insulin resistance, or family history of diabetes/premature CAD, MBF was measured with (13)N-ammonia and PET at baseline, during CPT, and during pharmacologic hyperemia. RESULTS: Sympathetic stimulation with CPT raised heart rate and blood pressure and thus MBF (Delta MBF=0.23+/-0.09 ml/min/g). MBF response, defined in absolute flow units as the difference between CPT and baseline, was independent of age, gender, heart rate, and blood pressure and rate-pressure product (RPP) at baseline as well as plasma substrate and lipid levels with the exception of an association with HDL cholesterol (rho=0.40, p=0.005) but depended on the change in RPP from rest (rho=0.33, p=0.019). Finally, changes in coronary vascular resistance in response to CPT were associated with changes in pharmacologic vasodilation (rho=0.56, p<0.0001). CONCLUSION: MBF response to sympathetic stimulation with cold (NO-mediated endothelium-dependent vasomotion), reflecting the functional state of the coronary endothelium, was independent of gender, age, and resting heart conditions. It was modulated by HDL cholesterol levels, even in healthy volunteers, and also related to pharmacologically stimulated vasodilator capacity at the coronary vascular resistance level.

Usefulness of fractional flow reserve measurements to defer revascularization in patients with stable or unstable angina pectoris, non-ST-elevation and ST-elevation acute myocardial infarction, or atypical chest pain.

This study determined the safety of deferring coronary revascularization based on a fractional flow reserve (FFR) value > or = 0.75 in a series of consecutive unselected coronary patients with moderate coronary lesions, including patients with unstable angina, myocardial infarction (MI), and/or positive noninvasive test findings. The study included 201 consecutive coronary patients (mean age 62 +/- 10 years; 65% men) with 231 lesions evaluated by FFR measurement for which revascularization was deferred based on a FFR value > or = 0.75. Lesions associated with a positive noninvasive test result were those located in an artery supplying a myocardial territory in which myocardial ischemia was demonstrated by a noninvasive test. Cardiac events (cardiac death, MI, revascularization) and Canadian Cardiovascular Society angina class were evaluated at follow-up. Indications for coronary angiography included unstable angina or MI (62%), stable angina (30%), or atypical chest pain (8%). Forty-four patients (22%) had > or = 1 coronary lesion associated with a positive noninvasive test result in which FFR was evaluated. Mean FFR value was 0.87 +/- 0.06 and mean lesion percent diameter stenosis was 41 +/- 8%. At 11 +/- 6 months of follow-up, cardiac events occurred in 20 patients (10%), and no significant differences were observed between patients with unstable angina or MI and those with stable angina (9% vs 13%, p = 0.44) or between patients with and without lesions associated with positive noninvasive test results (9% vs 10%, p = 1.00). At the end of follow-up, 88% of patients were asymptomatic in angina class 0 or I, with no differences across various groups. In conclusion, these results suggest that patients with moderate coronary lesions can be safely managed without revascularization on the basis of FFR measurements, irrespective of clinical presentation and/or presence of positive noninvasive test results.

PET-measured heterogeneity in longitudinal myocardial blood flow in response to sympathetic and pharmacologic stress as a non-invasive probe of epicardial vasomotor dysfunction.

PURPOSE: We investigated whether a myocardial perfusion gradient during pharmacologically induced hyperemia also occurred during sympathetic stimulation with cold pressor testing (CPT), which commonly induces a paradoxical coronary vasoconstriction in individuals with coronary risk factors. METHODS: Myocardial blood flow (MBF) was measured in absolute units (ml/g/min) with 13N-ammonia and PET at rest, during CPT, and during pharmacologic vasodilation in 59 participants with coronary risk factors ("at risk") and in 43 healthy individuals (controls). MBF was assessed globally as mean MBF, and in the mid and mid-distal myocardium of the left ventricle (LV). A decrease in MBF from mid to mid-distal LV myocardium was defined as MBF difference indicative of a perfusion gradient. RESULTS: The change in mean MBF to CPT (DeltaMBF) in the at-risk group was significantly reduced compared with controls (0.05+/-0.19 vs 0.31+/-0.20 ml/g/min, p<0.0001), whereas mean MBF during pharmacologic vasodilation in the at-risk group tended to be lower than in controls (1.72+/-0.71 vs 2.00+/-0.64 ml/g/min, p=NS). Absolute MBFs during CPT and pharmacologic vasodilation were significantly lower in the mid-distal than in the mid LV myocardium, resulting in a significant MBF difference in the at-risk group (0.15+/-0.06 and 0.27+/-0.12 ml/g/min, p<0.0001) that was not observed in controls (0.007+/-0.05 and 0.014+/-0.10 ml/g/min, p=NS). In the at-risk group there was a significant correlation between the difference of mid to mid-distal MBF during CPT and that during pharmacologic vasodilation (r=0.43, p<0.004), suggesting functional alterations of epicardial vessels as the predominant cause for the observed MBF difference. CONCLUSION: The relative decrease in MBF from the mid to the mid-distal left-ventricular myocardium suggests an intracoronary pressure decline during CPT and pharmacologic vasodilation, which is likely to reflect an impairment of flow-mediated epicardial vasomotor function.

Relationship between increasing body weight, insulin resistance, inflammation, adipocytokine leptin, and coronary circulatory function.

OBJECTIVES: We sought to evaluate effects of obesity, insulin resistance, and inflammation on coronary circulatory function and its relationship to leptin plasma levels. BACKGROUND: It is not known whether obesity, commonly paralleled by insulin resistance, inflammation, and leptin, is independently associated with coronary circulatory dysfunction. METHODS: Myocardial blood flow (MBF) responses to cold pressor test (CPT) and pharmacologic vasodilation was measured with positron emission tomography and 13N-ammonia. Study participants were divided into three groups based on their body mass index (BMI, kg/m2): control, 20 < or = BMI <25 (n = 19); overweight, 25 < or = BMI <30 (n = 21); and obese, BMI >30 (n = 32). RESULTS: Body mass index was significantly correlated to the Homeostasis Model Assessment Index of insulin resistance and C-reactive protein levels (r = 0.60 and r = 0.47, p < 0.0001). Compared with control subjects, endothelium-related change in MBF (DeltaMBF) to CPT progressively declined in overweight and obese groups (0.32 +/- 0.09 vs. 0.21 +/- 0.19 and 0.07 +/- 0.16 ml/g/min; p < 0.03 and p < 0.0001). The dipyridamole-induced total vasodilator capacity was significantly lower in obese than in control subjects (1.77 +/- 0.51 vs. 2.04 +/- 0.37 ml/g/min, p < 0.02). On multivariate analysis, BMI (p < 0.012) and age (p < 0.035) were significant independent predictors of DeltaMBF. Finally, only in the obese group leptin plasma levels significantly correlated with DeltaMBF (r = 0.37, p < 0.036). CONCLUSIONS: Increased body weight is independently associated with abnormal coronary circulatory function that progresses from an impairment in endothelium-related coronary vasomotion in overweight individuals to an impairment of the total vasodilator capacity in obese individuals. The findings that elevated leptin plasma levels in patients that are obese might exert beneficial effects on the coronary endothelium to counterbalance the adverse effects of increases in body weight on coronary circulatory function should be tested.

Coronary circulatory dysfunction in insulin resistance, impaired glucose tolerance, and type 2 diabetes mellitus.

BACKGROUND: Abnormal coronary endothelial reactivity has been demonstrated in diabetes and is associated with an increased rate of cardiovascular events. Our objectives were to investigate the presence of functional coronary circulatory abnormalities over the full spectrum of insulin resistance and to determine whether these would differ in severity with more advanced states of insulin resistance. METHODS AND RESULTS: Myocardial blood flow (MBF) was measured with positron emission tomography and 13N-ammonia to characterize coronary circulatory function in states of insulin resistance without carbohydrate intolerance (IR), impaired glucose tolerance (IGT), and normotensive and hypertensive type 2 diabetes mellitus (DM) compared with insulin-sensitive (IS) individuals. Indices of coronary function were total vasodilator capacity (mostly vascular smooth muscle-mediated) during pharmacological vasodilation and the nitric oxide-mediated, endothelium-dependent vasomotion in response to cold pressor testing. Total vasodilator capacity was similar in normoglycemic individuals (IS, IR, and IGT), whereas it was significantly decreased in normotensive (-17%) and hypertensive (-34%) DM patients. Compared with IS, endothelium-dependent coronary vasomotion was significantly diminished in IR (-56%), as well as in IGT and normotensive and hypertensive diabetic patients (-85%, -91%, and -120%, respectively). CONCLUSIONS: Progressively worsening functional coronary circulatory abnormalities of nitric oxide-mediated, endothelium-dependent vasomotion occur with increasing severity of insulin-resistance and carbohydrate intolerance. Attenuated total vasodilator capacity accompanies the more clinically evident metabolic abnormalities in diabetes.

Chronic inflammation and impaired coronary vasoreactivity in patients with coronary risk factors.

BACKGROUND: The goal of this study was to examine a possible association between systemic microinflammation, as reflected by C-reactive protein (CRP) serum levels, and coronary vasomotion in patients with coronary risk factors but with angiographically normal coronary arteries. METHODS AND RESULTS: Coronary vasomotor function was studied in response to cold pressor testing (CPT) in 71 patients with normal angiograms. In all patients, CPT-induced changes in epicardial luminal area (LA; mm2) were assessed with quantitative angiography. Within 20 days, myocardial blood flow (MBF) responses to CPT were measured (mL x g(-1) x min(-1)) noninvasively with 13N-ammonia and PET imaging. The CPT-induced mean changes in LA and in MBF in patients with elevated CRP (> or =0.5 mg/dL) were significantly impaired compared with patients presenting with CRP levels within normal range (<0.5 mg/dL) (DeltaLA, -1.09+/-0.86 versus 0.45+/-0.63 mm2; DeltaMBF, 0.06+/-0.18 versus 0.44+/-0.31 mL x g(-1) x min(-1); P<0.0001, respectively). Coronary LA changes and MBF responses to CPT were inversely correlated with CRP serum levels (r=-0.84 and r=-0.63; P<0.0001). Lastly, regression analysis revealed a significant correlation between the changes in LA and MBF during CPT for patients with elevated CRP levels and those for patients with normal CRP levels (r=0.56 and r=0.66; P<0.001). CONCLUSIONS: These findings suggest a direct association between systemic microinflammation and altered coronary vasomotor function of both the epicardial conductance and the arteriolar resistance vessels.

Myocardial viability in patients with ischemic cardiomyopathy-evaluation by 3-D integration of myocardial scintigraphic data--and coronary angiographic data.

PURPOSE: To determine the prevalence of viable myocardium in patients with ischemic cardiomyopathy and, to evaluate the value of three-dimensional (3-D) fusion imaging of myocardial scintigraphic and angiographic data to assign coronary artery lesions to the corresponding viable and nonviable myocardial territory. PROCEDURES: In 105 patients, the combination of perfusion and metabolic imaging with (201)thallium ((201)TI) single-photon emission computed tomography (SPECT) and 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) determined viability in dysfunctional myocardium. In addition, the value of 3-D scintigraphic fusion imaging was assessed in these patients. RESULTS: Based on the presence of viable dysfunctional myocardium, 54% of patients with ischemic cardiomyopathy may be considered for coronary revascularization. In 31 of 105 patients, the 3-D fusion imaging was estimated to be helpful in the diagnostic and interpretative process. CONCLUSION: In patients with end-stage coronary artery disease scintigraphic imaging is most important in the decision-making process. Three-dimensional fusion imaging may add important information in approximately 30% of these patients.

PET-measured responses of MBF to cold pressor testing correlate with indices of coronary vasomotion on quantitative coronary angiography.

UNLABELLED: The aims of this study were to determine whether responses in myocardial blood flow (MBF) to the cold pressor testing (CPT) method noninvasively with PET correlate with an established and validated index of flow-dependent coronary vasomotion on quantitative angiography. METHODS: Fifty-six patients (57 +/- 6 y; 16 with hypertension, 10 with hypercholesterolemia, 8 smokers, and 22 without coronary risk factors) with normal coronary angiograms were studied. Biplanar end-diastolic images of a selected proximal segment of the left anterior descending artery (LAD) (n = 27) or left circumflex artery (LCx) (n = 29) were evaluated with quantitative coronary angiography in order to determine the CPT-induced changes of epicardial luminal area (LA, mm(2)). Within 20 d of coronary angiography, MBF in the LAD, LCx, and right coronary artery territory was measured with (13)N-ammonia and PET at baseline and during CPT. RESULTS: CPT induced on both study days comparable percent changes in the rate x pressure product (%DeltaRPP, 37% +/- 13% and 40% +/- 17%; P = not significant [NS]). For the entire study group, the epicardial LA decreased from 5.07 +/- 1.02 to 4.88 +/- 1.04 mm(2) (DeltaLA, -0.20 +/- 0.89 mm(2)) or by -2.19% +/- 17%, while MBF in the corresponding epicardial vessel segment increased from 0.76 +/- 0.16 to 1.03 +/- 0.33 mL x min(-1) x g(-1) (DeltaMBF, 0.27 +/- 0.25 mL x min(-1) x g(-1)) or 36% +/- 31% (P