Coronary Flow Reserve Values Research Articles

Non-invasive assessment of coronary flow reserve and ADMA levels: a case-control study of early rheumatoid arthritis patients

Plasma concentration of asymmetric dimethylarginine (ADMA), a major endogenous inhibitor of nitric oxide synthase, is considered a novel risk factor for endothelial dysfunction associated with enhanced atherosclerosis. Coronary microcirculation abnormalities have been demonstrated in patients with early rheumatoid arthritis (ERA) without any signs or symptoms of coronary artery disease (CAD). The aim of the study was to compare the ERA and control groups with ADMA, intima-media thickness (IMT) and coronary flow reserve (CFR) levels. It assessed whether ERA patients have more cardiovascular risk (endothelial dysfunction and coronary microvascular abnormalities), and evaluated whether any difference in IMT/CFR between ERA and controls can be explained by any difference in ADMA levels between the groups. The study involved 25 ERA patients (female/male 21/4; mean age 52.04 +/- 14.05 years; disease duration <or=12 months) and 25 healthy volunteers with no history or current signs of CAD or other traditional risk factors. Dipyridamole trans-thoracic stress echocardiography was preformed to evaluate CFR, and carotid ultrasound to measure the IMT of the common carotid arteries. Blood samples were obtained in order to assess ADMA levels before the patients had received any biological or non-biological DMARDs, or steroid therapy. CFR was significantly reduced in the ERA patients (2.5 +/- 0.5 vs 3.5 +/- 0.8; P <0.01). In particular, 6/25 (24%) had a CFR of <2 consistent with potentially dangerous coronary flow impairment. Common carotid IMT was significantly greater in the ERA patients, although still within the normal range (0.68 +/- 0.1 vs 0.56 +/- 0.11 mm; P <0.01). There was a significant correlation between CFR and plasma ADMA levels in the ERA population (r = -0.53; P <0.01). IMT was negatively associated with CFR (P <0.05). Plasma ADMA levels were significantly higher in the ERA patients. A statistically significant negative effect of ADMA levels on CFR value was observed. The effect of ADMA levels on IMT is not significant.

Prognostic correlates of combined coronary flow reserve assessment on left anterior descending and right coronary artery in patients with negative stress echocardiography by wall motion criteria

Aims:To assess the prognostic correlates of Doppler echocardiographically derived coronary flow reserve (CFR) on two coronaries in patients with negative stress echo. Vasodilator stress echocardiography allows dual imaging of regional...

Acute Effects of Smoking Light Cigarettes on Coronary Microvascular Functions

To date, there has been no study comparing the possible acute effects on coronary microvascular functions of smoking light cigarettes (those with low tar and nicotine yield) and regular cigarettes. Twenty healthy volunteers (8 women and 12 men; mean age, 25.8 +/- 5.8 years) were included in a single-blind, open-label, cross-over study to compare the effects of smoking light cigarettes (containing 0.6 mg nicotine, 8 mg tar, 9 mg carbon monoxide) and smoking regular cigarettes (containing 0.9 mg nicotine, 12 mg tar, 12 mg carbon monoxide) on coronary flow reserve (CFR). For each participant, CFR values were measured at baseline, after smoking 2 regular or light cigarettes, and 15 days later after smoking 2 cigarettes of the other kind. After smoking 2 cigarettes, CFR values declined from 2.8 +/- 0.56 (baseline) to 2.31 +/- 0.51 after smoking light cigarettes (P = .003), and from 2.8 +/- 0.56 (baseline) to 2.21 +/- 0.45 after smoking regular cigarettes (P < .001). After smoking light and regular cigarettes, CFR values were similar (P = .678). Light cigarette smoking has similar acute detrimental effects on coronary microvascular function and CFR as does regular cigarette smoking.

Repeatability of regional myocardial blood flow calculation in 82Rb PET imaging

BackgroundWe evaluated the repeatability of the calculation of myocardial blood flow (MBF) at rest and pharmacological stress, and calculated the coronary flow reserve (CFR) utilizing 82Rb PET imaging. The aim of the research was to prove high repeatability for global MBF and CFR values and good repeatability for regional MBF and CFR values. The results will have significant impact on cardiac PET imaging in terms of making it more affordable and increasing its use.Methods12 normal volunteers were imaged at rest and during pharmacological stress, with 2220 MBq of 82Rb each. A GE Advance PET system was used to acquire dynamic 50-frame studies. MBF was calculated with a 2-compartmental model using a modified PMOD program (PMOD; University Hospital Zurich, Zurich, Switzerland). Two differential equations, describing a 2-compartmental model, were solved by numerical integration and using Levenberg-Marquardt's method for fitting data. The PMOD program defines 16 standard segments and calculates myocardial flow for each segment, as well as average septal, anterior, lateral, inferior and global flow. Repeatability was evaluated according to the method of Bland and Altman.ResultsGlobal rest and stress MBF, as well as global CFR, showed very good repeatability. No significant differences were found between the paired resting global MBF (0.63 ± 0.13 vs. 0.64 ± 0.13 mL/min/g; mean difference, -1.0% ± 2.6%) and the stress global MBF (1.37 ± 0.23 vs. 1.37 ± 0.24; mean difference, 0.1% ± 2.3%). Global CFR was highly reproducible (2.25 ± 0.56 vs. 2.22 ± 0.54, P = not statistically significant; mean difference, 1.3% ± 14.3%). Repeatability coefficients for global rest MBF were 0.033 (5.2%) and stress MBF 0.062 (4.5%) mL/min/g. Regional rest and stress MBF and CFR have shown good reproducibility. The average per sector repeatability coefficients for rest MBF were 0.056 (8.5%) and stress MBF 0.089 (6.3%) mL/min/g, and average repeatability coefficient for CFR was 0.25 (10.6%).ConclusionThe results of the study show that software calculation of MBF and CFR with 82Rb myocardial PET imaging is highly repeatable for global values and has good repeatability for regional values.

Diffuse, marked, reversible impairment in coronary microcirculation in stress cardiomyopathy: A Doppler transthoracic echo study

The aim of the study was to assess coronary flow reserve (CFR) in tako-tsubo cardiomyopathy (TC).Methods and results. Thirty consecutive patients (5 males; age 68±12 years) meeting diagnostic criteria for TC were evaluated with transthoracic dipyridamole (0.84 mg/kg over 6 min) stress echo and pulsed Doppler CFR assessment on mid-distal left anterior descending (LAD) and posterior descending of right coronary artery (PD). Wall motion score index (WMSI) was evaluated at base-line and during stress. All patients were followed up clinically and—on day 1, day 7 (±2 days), and at 6 months—by repeat stress echo. Thirty gender- matched controls were also studied. CFR was obtained in all patients on LAD and in 25 on PD. All showed a transient apical ballooning in the acute phase (day 1 of admission), with progressive recovery of function at follow-up (WMSI, day 1 = 1.7±0.2; day 7 = 1.4±0.14; 6 months = 1.0±0.1; P<0.001 versus day 1 and versus day 7). When compared to controls (3.1±0.5), CFR on LAD was reduced on day 1 (1.8±0.24, P<0.001) (upon admission), and it showed early recovery in the subacute (pre-discharge) assessment on day 7. CFR values remained stable at 6-month follow-up (2.6±0.3).Conclusion. TC is characterized by a profound, diffuse coronary microcirculatory disturbance in the acute phase, with early reversal to near-normal values within a few days, paralleling the functional recovery in regional wall motion.

Additive Prognostic Value of Coronary Flow Reserve in Patients With Chest Pain Syndrome and Normal or Near-Normal Coronary Arteries

In patients with angiographically normal coronary arteries and chest pain, pharmacologic stress echocardiography can identify a subgroup of patients with a less benign prognosis. Coronary flow reserve (CFR) in the left anterior descending artery (LAD) can currently be combined with wall motion analysis during vasodilator stress echocardiography. The aim of this study was to assess the prognostic value of CFR response in patients with normal coronary arteries and normal wall motion during stress. We selected 394 patients (171 men, 61 +/- 11 years of age) who underwent dipyridamole stress echocardiography (0.84 mg/kg over 6 minutes) with 2-dimensional echocardiography and CFR evaluation of the LAD by Doppler. All had angiographically nonsignificant (<50% quantitatively assessed) stenosis in any major vessel, normal left ventricular function (wall motion score index 1), and test negativity for conventional wall motion criteria. Images were independently read by a core laboratory for wall motion and a core laboratory for CFR. Mean CFR was 2.5 +/- 0.6 and 87 patients (22%) had an abnormal CFR <2. During a median follow-up of 51 months, 31 events occurred, namely 4 deaths and 27 nonfatal myocardial infarctions (3 ST-elevated myocardial infarctions and 24 non-ST-elevated myocardial infarctions). Kaplan-Meier survival estimates for hard events showed a better outcome for those patients with a normal CFR compared with those with an abnormal CFR (96% vs 55%, p = 0.001, at 48 months of follow-up). In conclusion, in patients with angiographically normal or near-normal coronary arteries and preserved at-rest regional and global left ventricular function at baseline and during stress, CFR adds incremental value to the prognostic stratification achieved with clinical and angiographic data.

Coronary flow reserve dysfunction in hemodialysis and kidney transplant patients

The assessment of coronary flow reserve (CFR) by trans-thoracic echocardiography has recently been introduced into clinical studies. Impairment of coronary microvascular functions and decreased CFR detected by trans-thoracic Doppler harmonic echocardiography (TTDE) has recently been reported in hemodialysis (HD) patients, but there is no comparative study between HD patients and renal transplant recipients. The aim of our study was to evaluate coronary microvascular circulation in chronic HD patients and renal transplant recipients. Forty-eight chronic HD patients, 27 renal transplant patients and 39 normotensive healthy controls were studied for the assessment of CFR by TTDE. The carotid artery intima media thickness (IMT) and areas of focal plaque formation were also evaluated in all subjects. CFR values were significantly lower in both the HD and renal transplant groups than in the control group (p = 0.00). CFR values (1.57 +/- 0.32 vs. 1.89 +/- 0.50, p = 0.01) were also significantly lower in the HD group than in the renal transplant group. In 43 of 48 (89.6%) HD patients, CFR was <2.0; however, in 16 of 27 (59.3%) renal transplant recipients it was <2.0 (p = 0.00). When the HD and renal transplant groups were divided into two subgroups, according to CFR measurements (CFR < 2 and > or =2), no significant differences were found with respect to coronary risk factors and left ventricular echocardiographic measurements. The IMT of the control group (0.586 +/- 0.163 mm) was significantly lower than the HD (0.799 +/- 0.218 mm) and renal transplant groups (0.681 +/- 0.148 mm; p = 0.00). The IMT of the HD patients (0.799 +/- 0.218 mm) was significantly higher than the renal transplant recipients (0.681 +/- 0.148 mm; p = 0.01). Renal transplant and HD patients had lower CFR values detected by TTDE, which may be regarded as an early finding of an affected cardiovascular system. CFR is more impaired in HD patients than renal transplant recipients. Uremia-associated microvascular disease may be responsible for CFR impairment in HD patients.

Impairment of coronary flow reserve in aortic stenosis

Coronary flow reserve (CFR) is markedly reduced in patients with severe aortic valve stenosis (AS), but the exact mechanisms underlying this impairment of CFR in AS remain unclear. Reduced CFR is the key mechanism leading to myocardial ischemia symptoms and adverse outcomes in AS patients. The objective of this study was to develop an explicit mathematical model formulated with a limited number of parameters that describes the effect of AS on left coronary inflow patterns and CFR. We combined the mathematical V(3) (ventricular-valvular-vascular) model with a new lumped-parameter model of coronary inflow. One thousand Monte-Carlo computational simulations with AS graded from mild up to very severe were performed within a wide range of physiological conditions. There was a good agreement between the CFR values computed with this new model and those measured in 24 patients with isolated AS (r = 0.77, P < 10(-4)). A global sensitivity analysis showed that the valve effective orifice area (EOA) was the major physiological determinant of CFR (total sensitivity index = 0.87). CFR was markedly reduced when AS became severe, i.e., when EOA was <1.0 cm(2), and was generally exhausted when the EOA was <0.5-0.6 cm(2). The reduction of CFR that is associated with AS can be explained by the concomitance of 1) reduced myocardial supply as a result of decreased coronary perfusion pressure, and 2) increased myocardial metabolic demand as a result of increased left ventricular workload.

Abstract 4234: Prognostic Implication of the Continuous Prognostic Spectrum of Coronary Flow Reserve in Patients with and without Angiographically Obstructive Coronary Artery Disease

Dual imaging of wall motion and coronary flow reserve (CFR) on left anterior descending (LAD) artery is now the state-of-the art technique for vasodilator stress echo. The additive prognostic value of CFR over regional wall motion has been established, but there is more than a binary (normal-abnormal ) response in CFR, which can be continuously titrated. Objectives. To assess the prognostic value of Doppler echocardiographic derived CFR in patients with and without angiographically obstructive coronary artery disease (CAD). 1244 patients (785 men, age 64±11 yy) with known or suspected CAD underwent dipyridamole (up to 0.84 mg/kg over 6′) stress echo with CFR evaluation of left anterior descending artery by Doppler and coronary angiography. Patients were followed-up for a median of 17 months. Mean CFR in the entire population was 2.25±0.64. During follow-up, there were 227 events (26 deaths, 55 STEMI, and 146 NSTEMI). Patients (n=384) undergoing revascularization were censored. Using the Kaplan-Meier method, the lowest quartile of CFR (&lt;1.80) was associated with a significantly (p&lt;0.0001) worst event rate than other quartiles (Figure ), both considering the group with (83 vs 53%, p&lt;0.0001) and without (53 vs 12%, p&lt;0.0001) obstructive CAD at angiography. CFR is a strong and independent prognostic predictor in patients with known or suspected CAD, but the spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale rather than artificially dichotomized.

Abstract 4838: Diffuse, Marked, Reversible Impairment in Coronary Microcirculation in Stress Cardiomyopathy: A Vasodilator Stress Echo Study

Stress cardiomyopathy, also referred to as Takotsubo cardiomyopathy (TC) has been linked to excessive sympathetic stimulation, which can be toxic for myocytes and coronary microcirculation. Aim: To assess coronary flow reserve (CFR) in TC. Methods: 30 consecutive patients (5 males; 68±12 years) meeting diagnostic criteria for TC were evaluated with transthoracic dipyridamole (0.84 mg/kg over 6′) stress echo and Pulsed Doppler CFR assessment on mid-distal left anterior descending (LAD) and posterior descending of right coronary artery (PD). Wall Motion Score Index (WMSI) was evaluated at baseline and during stress. All patients were followed-up clinically and - on day 1, day 7 (±2 days) and at 6 months - by repeat stress echo. Twenty-one age and gender matched controls were also studied. Results: CFR was obtained in all patients on LAD and in 25 on PD. All pts showed a transient apical ballooning in the acute phase (day 1 of admission), with progression recovery of function at follow-up (WMSI, day 1=1.7±.2; day 7=1.4±.14; 6-months=1.0±0.1; p&lt;0.001 vs day 1 and vs. day 7). When compared to controls, CFR was reduced on day 1 (upon admission) and it showed early recovery in the subacute (pre-discharge) assessment on day 7. CFR values remained stable at 6-months follow-up (see figure ). Conclusion: TC is characterized by a profound, diffuse, coronary microcirculatory disturbance in the acute phase, with early reversal to near-normal values within a few days, paralleling the functional recovery in regional wall motion. The reversible coronary microcirculatory abnormality can be observed also in the territory of right coronary artery.

Transthoracic Doppler Echocardiographic Coronary Flow Imaging in Identification of Left Anterior Descending Coronary Artery Stenosis in Patients with Left Bundle Branch Block

Conventional noninvasive methods have well-known limitations for the detection of coronary artery disease (CAD) in patients with left bundle branch block (LBBB). However, advancements in Doppler echocardiography permit transthoracic imaging of coronary flow velocities (CFV) and measurement of coronary flow reserve (CFR). Our aim was to evaluate the diagnostic value of transthoracic CFR measurements for detection of significant left anterior descending (LAD) stenosis in patients with LBBB and compare it to that of myocardial perfusion scintigraphy (MPS). Simultaneous transthoracic CFR measurements and MPS were analyzed in 44 consecutive patients with suspected CAD and permanent LBBB. Typical diastolic predominant phasic CFV Doppler spectra of distal LAD were obtained at rest and during a two-step (0.56-0.84 mg/kg) dipyridamole infusion protocol. CFR was defined as the ratio of peak hyperemic velocities to the baseline values. A reversible perfusion defect at LAD territory was accepted as a positive scintigraphy finding for significant LAD stenosis. A coronary angiography was performed within 5 days of the CFR studies. The hyperemic diastolic peak velocity (44 +/- 9 cm/sec vs 62 +/- 2 cm/sec; P=0.01) and diastolic CFR (1.38 +/- 0.17 vs 1.93 +/- 0.3; P=0.001) were significantly lower in patients with LAD stenosis compared to those without LAD stenosis. The diastolic CFR values of <1.6 yielded a sensitivity of 100% and a specificity of 94% in the identification of significant LAD stenosis. In comparison, MPS detected LAD stenosis with a sensitivity of 100% and a specificity of 29%. CFR measurement by transthoracic Doppler echocardiography is an accurate method that may improve noninvasive identification of LAD stenosis in patients with LBBB.

Prognostic Implications of Coronary Flow Reserve on Left Anterior Descending Coronary Artery in Hypertrophic Cardiomyopathy

The aim of the study was to prospectively evaluate a cohort of patients with hypertrophic cardiomyopathy (HC) after coronary flow reserve (CFR) assessment of the left anterior descending coronary artery. Sixty-eight patients with HC (40 men, mean +/- SD 58 +/- 12 years of age) underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) echocardiography with CFR evaluation of the left anterior descending coronary artery by Doppler. Seventy-four age- and gender-matched, apparently healthy subjects served as controls. A CFR value <2.0 was considered abnormal. CFR was decreased in patients with HC versus controls (2.12 +/- 0.39 vs 2.78 +/- 0.58, p <0.0001). CFR was abnormal in 26 of 39 symptomatic and in 5 of 29 asymptomatic patients with HC (67% vs 17%, p <0.0001). In addition, patients with HC with left ventricular obstruction had decreased CFR (p <0.0001) compared with those without obstruction. During follow-up (22 +/- 13 months), 27 events occurred: 1 sudden death, 1 nonfatal myocardial infarction, 4 cardioverter-defibrillator implantations, 6 hospitalizations for heart failure, 5 unstable anginas, 2 syncopes, and 8 atrial fibrillations. Three-year event rate was markedly higher in patients with abnormal than in those with normal CFR (79% vs 17%, p <0.0001). Events were more frequent in symptomatic than in asymptomatic patients (62% vs 10%, p <0.0001). However, the latter had a 10-fold increased risk of events in the presence of abnormal CFR (40% vs 4%, p = 0.02). In conclusion, mean CFR is markedly lower in patients with HC than in apparently healthy subjects. Abnormal CFR is a strong and independent predictor of outcome in patients with HC.

Coronary microvascular function in Takotsubo cardiomyopathy: Results of non-invasive evaluation

The role of coronary microvascular function in Takotsubo cardiomyopathy remains to be elucidated. In this study it was evaluated through coronary flow reserve (CFR) by means of transthoracic Doppler ultrasound imaging of the left anterior descending (LAD) coronary artery in 5 consecutive patients without risk factors and/or concomitant diseases impairing, per se, coronary microcirculation. In each case CFR values were in the normal range and not significantly different from age and sex-matched control subjects. These data suggest that coronary microvascular function may not be impaired in Takotsubo patients when negative influences by concomitant diseases and coronary risk factors are excluded.

The prognostic value of Doppler echocardiographic-derived coronary flow reserve is not affected by concomitant antiischemic therapy at the time of testing

When wall motion abnormality is the diagnostic end point, concomitant antiischemic therapy heavily modulates the prognostic value of dipyridamole echocardiography test (DET). A negative test result is less benign, and a positive test result is more malignant if performed under therapy. Recently, coronary flow reserve (CFR) was added to wall motion in dual imaging DET. The aim of the study was to determine whether antianginal medications affect the prognostic value of Doppler echocardiographic-derived CFR in patients with known or suspected coronary artery disease undergoing DET. In a prospective, multicenter, observational study, we evaluated 1,779 patients (1,072 males; 64 +/- 11 years) who underwent high-dose dipyridamole (0.84 mg/kg for 6 minutes) stress echo with CFR evaluation of left anterior descending (LAD) artery by Doppler. Seven hundred thirty-three (41%) patients were on antiischemic therapy at time of testing (nitrates and/or calcium antagonists and/or beta-blockers). Mean CFR was 2.3. +/- 0.6. At individual patient analysis, 1,141 patients had normal (CFR >2.0) and 638 had abnormal (CFR <or=2.0) CFR on LAD. During a median follow-up of 36 months, 263 events occurred as follows: 36 deaths and 59 ST-elevation myocardial infarctions (STEMIs) and 168 non-STEMIs (NSTEMIs). Survival was highest in patients with normal CFR and lowest in patients with abnormal CFR (87% vs 34%, P = .0001). Survival was comparable in patients with normal CFR on and off therapy and in patients with abnormal CFR on and off therapy. At multivariable analysis, hypertension (hazard ratio [HR] 1.5, 95% CI 1.0-1.9, P = .010), DET positivity for regional wall motion abnormalities (HR 5.7, 95% CI 4.3-7.4, P = .000), an abnormal CFR on LAD (HR 3.3, 95% CI 2.5-4.4, P = .000) were independent prognostic predictors of hard cardiac events. Ongoing antiischemic therapy at the time of testing does not modulate the prognostic value of Doppler echocardiographic-derived coronary flow reserve.

Evaluation of coronary microvascular function in patients with end-stage renal disease, and renal allograft recipients

Background Approximately half of all deaths in patients with end-stage renal disease (ESRD) are due to cardiovascular diseases. Although renal transplant improves survival and quality of life in these patients, cardiovascular events significantly affect survival. We sought to evaluate coronary flow reserve (CFR), an indicator of coronary microvascular function, in patients with ESRD and in patients with a functioning kidney graft. Methods Eighty-six patients (30 with ESRD, 30 with a functioning renal allograft, and 26 controls) free of coronary artery disease or diabetes mellitus were included. Transthoracic Doppler echocardiography was used to measure coronary peak flow velocities at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities and was compared among the groups. Results The mean age of the study population was 36.1 ± 7.3 years. No between-group differences were found regarding age, sex, or prevalences of traditional coronary risk factors other than hypertension. Compared with the renal transplant and control groups, the ESRD group had significantly lower mean CFR values. On multivariate regression analysis, serum levels of creatinine, age, and diastolic dysfunction were independent predictors of CFR. Conclusions CFR is impaired in patients with ESRD suggesting that coronary microvascular dysfunction, an early finding of atherosclerosis, is evident in these patients. Although associated with a decreased CFR compared with controls, renal transplant on the other hand seems to have a favorable effect on coronary microvascular function.

Prognostic value of coronary flow reserve and aortic distensibility indices in patients with suspected coronary artery disease

In recent studies it has been demonstrated that a reduced coronary flow reserve (CFR) is independently associated with a less benign long-term outcome. Aortic stiffness is one of the most important cardiovascular risk factors predicting cardiovascular morbidity and mortality. Vasodilator stress transesophageal echocardiography (TEE) is a suitable method to evaluate simultaneously CFR and elastic properties of the descending thoracic aorta. The aim of the present study was to assess the relative prognostic value of simultaneously measured CFR and aortic elastic properties by pulsed-wave Doppler TEE in patients with suspected or known coronary artery disease (CAD). The study comprised 157 in-hospital patients with chest pain. In all patients, stress TEE was used for the simultaneous evaluation of CFR and aortic distensibility indices [elastic modulus E(p) and Young's circumferential static elastic modulus E(s)]. During a mean follow-up of 48 +/- 8 months, 13 patients suffered cardiovascular death. By univariate analysis older age, diabetes mellitus, increased left ventricular (LV) end-diastolic diameter, increased LV mass index, lower LV ejection fraction, and lower CFR were significant predictors of cardiovascular survival. Multivariate regression analysis showed that only CFR (hazard ratio [HR] 10.31, P = 0.04), age (HR 1.20, P = 0.001), and increased left ventricular (LV) end-diastolic diameter (HR 1.14, P = 0.02) were independent predictors of cardiovascular survival. Only in the small number of patients without CAD and abnormal CFR aortic distensibility seemed to provide complementary prognostic information over CFR. In the majority of patients aortic distensibility did not offer complementary prognostic information to CFR during vasodilator stress TEE testing.

Smoking mentholated cigarettes impairs coronary microvascular function as severely as does smoking regular cigarettes

Objective — Smoking mentholated cigarettes inhibits the metabolism of nicotine and increases systemic exposure to cigarette smoke toxins. However, the possible effects of smoking mentholated cigarettes on coronary microvascular functions are unknown.We sought to investigate whether smoking mentholated cigarettes impairs coronary flow reserve (CFR) more so than smoking regular cigarettes.Methods — Twenty otherwise healthy smokers of regular cigarettes (6 women, 14 men; mean age, 25.6 ± 6.4 years) and 22 non-smoking control subjects were included in the study.To compare the acute effects of mentholated (0.9 mg nicotine, 11 mg tar, 12 mg carbon monoxide) and regular (0.9 mg nicotine, 12 mg tar, 12 mg carbon monoxide) cigarettes on CFR, all subjects underwent an echocardiographic examination that included CFR measurements at baseline. Twenty to 30 minutes after subjects had smoked 2 regular cigarettes and 2 mentholated cigarettes, CFR was again measured in subjects in the smoking group.Results — In response to smoking 2 regular and 2 mentholated cigarettes, CFR values declined from 2.56 ± 0.60 to 2.06 ± 0.38 (P < 0.004) and from 2.56 ± 0.60 to 2.14 ± 0.30 (P < 0.005), respectively. Smoking mentholated and regular cigarettes impaired CFR to the same degree (P =0.547).Conclusions — When compared with smoking regular cigarettes, smoking mentholated cigarettes has similar acute detrimental effects on coronary microvascular functions.

Diagnosis of Coronary Restenosis Using Coronary Flow Reserve Measurements Obtained Through Transthoracic Doppler Echocardiography

Background and Objectives: Coronary flow reserve (CFR) decreases in the presence of significant coronary stenosis. Hence, CFR can be used for the detection of restenosis after percutaneous coronary intervention (PCI). However, because CFR can also be affected by other conditions such as endothelial dysfunction, microvascular damage, and left ventricular hypertrophy, the absolute value of CFR is not routinely used for detection of coronary restenosis. We hypothesized that changes in the value of CFR, rather than the absolute CFR value, are better correlated with restenosis in various clinical settings. Subjects and Methods: We studied 99 patients (71 males/28 females, mean age 58±11 years) who underwent successful PCI of the left anterior descending artery. Pre-PCI diagnoses were as follows: 37 unstable angina, 35 stable angina, 27 acute myocardial infarction. CFR using transthoracic Doppler was measured at 48 hours after PCI and at the time of follow-up angiography (6.0±1.5 months later). Coronary flow velocity was measured in the distal left anterior descending artery with a 7 MHz transducer (HDI 5,000, Philips, The Netherlands) at baseline and during intravenous infusion of adenosine (140 μg·kg-·min-). Mean diastolic coronary flow velocities from at least three cardiac cycles were averaged. Results: CFRs in 69 patients without restenosis were 2.55±0.99 at 48 hours after PCI and 2.93±1.00 at follow-up (p 50% in diameter stenosis) decreased significantly from 2.70± 1.01 at 48 hours after PCI to 1.98±0.91 at follow-up (p<0.001). There was a significant difference in CFR change (ratio of CFRfollowup/CFRinitial) between the two groups. CFR change had a better receiver operating characteristics (ROC) curve than absolute CFR for prediction of restenosis [area under the curve (AUC) for absolute CFR= 0.76, AUC for CFR change=0.82]. Conclusion: Restenosis after PCI leads to a significant decrease in CFR, even in the presence of variable baseline CFR values. Serial measurements of CFR can be used to detect restenosis after PCI. (Korean Circ J 2008;38:325-330)

Impaired coronary microvascular function and increased intima-media thickness in rheumatoid arthritis

Background Rheumatoid arthritis (RA) is associated with excessive cardiovascular mortality. Recently, some studies have shown endothelial dysfunction in RA patients with high inflammatory activity. In addition, it has been suggested that the chronic inflammatory state of RA contributes to accelerated atherosclerosis. Therefore, we aimed to evaluate whether coronary microvascular dysfunction and increased carotid artery intima-media thickness exist in patients with a long history and well controlled disease activity of RA lacking traditional cardiovascular risk factors. Methods Thirty RA patients (22 women; mean age 43.7 ± 9.0) and 52 healthy volunteers (38 women; mean age 45.3 ± 5.4) were included into the study. Using transthoracic echocardiography, each subject underwent echocardiographic examination including coronary flow reserve (CFR) and carotid intima-media thickness (IMT) measurement. Results CFR values were statistically reduced for RA patients as compared to controls (2.4 ± 0.5 vs. 2.7 ± 0.4, P = 0.002) whereas IMT values were significantly increased (0.6 ± 0.1 vs. 0.5 ± 0.1, P = 0.001). In RA patients, CFR positively correlated with lateral Em/Am ratio ( r = 0.399, P = 0.029), and negatively correlated with lateral isovolumic relaxation time (IVRT) ( r = −0.744, P = 0.005), IMT ( r = −0.542, P = 0.002) and RA disease duration ( r = −0.495, P = 0.005). Reflecting LV diastolic function, mitral E-wave deceleration time and isovolumic relaxation time were borderline significant between the groups, however lateral Em/Am ratio and lateral IVRT were statistically different. Conclusions Patients with RA had impaired CFR and increased carotid IMT, and these injurious effects correlated significantly with disease duration.

Coronary flow reserve after l-thyroxine therapy in Hashimoto’s thyroiditis patients with subclinical and overt hypothyroidism

Overt and subclinical hypothyroidism are reported to be associated with increased cardiovascular disease risk. We have used coronary flow reserve (CFR) measurement by trans-thoracic Doppler echocardiography (TTDE) to determine coronary microvascular function in Hashimoto's thyroiditis patients with overt and subclinical hypothyroidism and to evaluate effects of L-thyroxine replacement on coronary endothelial function. In total, 10 overt hypothyroid patients, 10 subclinical hypothyroid patients, and 10 controls were enrolled. FT4, TSH, anti-thyroid antibodies, lipid profile, insulin, glucose, HOMA-IR, physical parameters, and CFR measured by TTDE were recorded before and after 6 months of L: -thyroxine replacement in all groups. CFR values of all hypothyroid patients at baseline were significantly lower than those in controls. After L: -thyroxine, CFR increased significantly in overt and subclinical hypothyroidism with respect to the baseline measurements (P < 0.05). When baseline and second measurements were evaluated collectively for patients and controls, CFR was positively correlated with FT4 levels (r = 0.31, P = 0.01) and negatively correlated with TSH and HOMA-IR (r = -0.38, P = 0.002 and r = -0.42, P < 0.001, respectively). Subclinical as well as overt hypothyroid patients have impaired coronary microvascular function which improved after L: -thyroxine therapy. Treatment of Hashimoto's thyroiditis patients with subclinical hypothyroidism should be considered to improve cardiovascular disease risk.