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

Coronary flow reserve and cardiovascular outcomes: a systematic review and meta-analysis

AIMS

This meta-analysis aims to quantify the association of reduced coronary flow with all-cause mortality and major adverse cardiovascular events (MACE) across a broad range of patient groups and pathologies.

METHODS AND RESULTS

We systematically identified all studies between 1 January 2000 and 1 August 2020, where coronary flow was measured and clinical outcomes were reported. The endpoints were all-cause mortality and MACE. Estimates of effect were calculated from published hazard ratios (HRs) using a random-effects model. Seventy-nine studies with a total of 59 740 subjects were included. Abnormal coronary flow reserve (CFR) was associated with a higher incidence of all-cause mortality [HR: 3.78, 95% confidence interval (CI): 2.39-5.97] and a higher incidence of MACE (HR 3.42, 95% CI: 2.92-3.99). Each 0.1 unit reduction in CFR was associated with a proportional increase in mortality (per 0.1 CFR unit HR: 1.16, 95% CI: 1.04-1.29) and MACE (per 0.1 CFR unit HR: 1.08, 95% CI: 1.04-1.11). In patients with isolated coronary microvascular dysfunction, an abnormal CFR was associated with a higher incidence of mortality (HR: 5.44, 95% CI: 3.78-7.83) and MACE (HR: 3.56, 95% CI: 2.14-5.90). Abnormal CFR was also associated with a higher incidence of MACE in patients with acute coronary syndromes (HR: 3.76, 95% CI: 2.35-6.00), heart failure (HR: 6.38, 95% CI: 1.95-20.90), heart transplant (HR: 3.32, 95% CI: 2.34-4.71), and diabetes mellitus (HR: 7.47, 95% CI: 3.37-16.55).

CONCLUSION

Reduced coronary flow is strongly associated with increased risk of all-cause mortality and MACE across a wide range of pathological processes. This finding supports recent recommendations that coronary flow should be measured more routinely in clinical practice, to target aggressive vascular risk modification for individuals at higher risk.

Vasomotor Dysfunction in Patients with Ischemia and Non-Obstructive Coronary Artery Disease: Current Diagnostic and Therapeutic Strategies

Many patients who present with symptoms or objective evidence of ischemia have no or non-physiologically-significant disease on invasive coronary angiography. The diagnosis of ischemic heart disease is thus often dismissed, and patients receive false reassurance or other diagnoses are pursued. We now know that a significant proportion of these patients have coronary microvascular dysfunction and/or vasospastic disease as the underlying pathophysiology of their clinical presentation. Making the correct diagnosis of such abnormalities is important not only because they impact the quality of life, with recurring symptoms and unnecessary repeated testing, but also because they increase the risk for adverse cardiovascular events. The mainstay of diagnosis remains an invasive comprehensive physiologic assessment, which further allows stratifying these patients into appropriate “endotypes”. It has been shown that tailoring treatment to the patient’s assigned endotype improves symptoms and quality of life. In addition to the conventional drugs used in chronic stable angina, multiple newer agents are being investigated. Moreover, innovative non-pharmacologic and interventional therapies are emerging to provide a bail-out in refractory cases. Many of these novel therapies fail to show consistent benefits, but others show quite promising results.

Apparent Declining Prognostic Value of a Negative Stress Echocardiography Based on Regional Wall Motion Abnormalities in Patients With Normal Resting Left Ventricular Function Due to the Changing Referral Profile of the Population Under Study

Background Cardiology guidelines identify the low-risk response during stress echocardiography as the absence of regional wall motion abnormalities. Methods From 1983 to 2016, we enrolled 5817 patients (age 63±12 years; 2830 males) with suspected coronary artery disease, normal regional, and global left ventricular function at rest and during stress (exercise in 692, dipyridamole in 4291, and dobutamine in 834). Based on timing of enrollment, 4 groups were identified in chronological order of recruitment: years 1983 to 1989, group 1 (n=211); years 1990 to 1999, group 2 (n=1491); years 2000 to 2009, group 3 (n=3285); and years 2010 to 2016, group 4 (n=830). Results There were 240 (4%) events (119 deaths and 121 infarctions) in the follow-up. At 1-year follow-up, the event rate was 0.5% (95% CI, 0.05-0.95), 1.5% (95% CI, -1.18 to 1.82), 1.9% (95% CI, 1.63-2.17), and 1.7% (95% CI, 1.01-2.39; χ², 9.0; P=0.03) in groups 1 to 4, respectively. At multivariable Cox analysis, independent predictors of future events were age (hazard ratio (HR), 1.05; 95% CI, 1.04-1.07; P<0.0001), male sex (HR, 1.57; 95% CI, 1.20-2.04; P=0.001), diabetes mellitus (HR, 1.78; 95% CI, 1.34-2.37; P<0.0001), smoking habit (HR, 1.40; 95% CI, 1.05-1.85; P=0.02), and ongoing anti-ischemic therapy (HR, 1.50; 95% CI, 1.15-1.97; P=0.003) Conclusions Over the past 3 decades, we observed a progressive decline in the prognostic value of a negative test based on regional wall motion abnormalities, likely reflecting both an increase in risk in patients, as well as a potential decrease in test performance due to concomitant anti-ischemic therapy.

Stress echocardiography in coronary artery disease: a practical guideline from the British Society of Echocardiography

Stress echocardiography is an established technique for assessing coronary artery disease. It has primarily been used for the diagnosis and assessment of patients presenting with chest pain in whom there is an intermediate probability of coronary artery disease. In addition, it is used for risk stratification and to guide revascularisation in patients with known ischaemic heart disease. Although cardiac computed tomography has recently been recommended in the United Kingdom as the first-line investigation in patients presenting for the first time with atypical or typical angina, stress echocardiography continues to have an important role in the assessment of patients with lesions of uncertain functional significance and patients with known ischaemic heart disease who represent with chest pain. In this guideline from the British Society of Echocardiography, the indications and recommended protocols are outlined for the assessment of ischaemic heart disease by stress echocardiography.

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Drop-off in positivity rate of stress echocardiography based on regional wall motion abnormalities over the last three decades

Previous studies have suggested a decline in positivity of stress cardiac imaging based on regional wall motion abnormalities (RWMA). To assess the rate of RWMA positivity of stress echocardiography (SE) over 3 decades in the same primary care SE lab. We retrospectively assessed the rate of SE positivity in 7626 SE tests (dipyridamole in 5053, dobutamine in 2496, exercise in 77) in consecutive patients with known or suspected coronary artery disease and /or heart failure who performed SE in a primary care referral center from April 1991 to May 2018. Starting April 2005, SE based on RWMA was complemented by assessment of coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery. Starting October 2016, we added left ventricular contractile reserve (LVCR). Starting October 2016, we also added B-lines by lung ultrasound. There was a progressive decline over time in the rate of SE positivity based on RWMA from 24% (1991-1999) to 10% (2000-2009) down to 4% (2010-2018) (p < 0.0001). Positivity rate was 29% with CFVR, 16% with LVCR, and 12% with B-lines. Over three decades, we observed a dramatic decline in SE positivity rate based on classical RWMA. In the last decade, the positivity rate rose sharply thanks to the stepwise introduction of CFVR, LVCR and B-lines as additional positivity criteria in integrated quadruple SE.

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

BACKGROUND

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

INTEGRATED-QUADRUPLE STRESS-ECHO

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In "ABCD" protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

CONCLUSION

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous "ABCD" protocol.

Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients with Nonculprit Stenosis of Intermediate Severity Early after Primary Percutaneous Coronary Intervention

BACKGROUND

Treatment of nonculprit coronary stenosis during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction may be beneficial, but the mode and timing of the intervention are still controversial. The aim of this study was to examine the significance and prognostic value of preserved coronary flow velocity reserve (CFVR) in patients with nonculprit intermediate stenosis early after primary percutaneous coronary intervention.

METHODS

Two hundred thirty patients with remaining intermediate (50%-70%) stenosis of non-infarct-related arteries, in whom CFVR was performed within 7 days after primary percutaneous coronary intervention, were prospectively enrolled. Twenty patients with reduced CFVR and positive results on stress echocardiography or impaired fractional flow reserve underwent revascularization and were not included in further analysis. The final study population of 210 patients (mean age, 58 ± 10 years; 162 men) was divided into two groups on the basis of CFVR: group 1, CFVR > 2 (n = 174), and group 2, CFVR ≤ 2 (n = 36). Cardiac death, nonfatal myocardial infarction, and revascularization of the evaluated vessel were considered adverse events.

RESULTS

Mean follow-up duration was 47 ± 16 months. Mean CFVR for the whole group was 2.36 ± 0.40. There were six adverse events (3.4%) related to the nonculprit coronary artery in group 1, including one cardiac death, one ST-segment elevation myocardial infarction, and four revascularizations. In group 2, there were 30 adverse events (83.3%, P < .001 vs group 1), including two cardiac deaths, two ST-segment elevation myocardial infarctions, and 26 revascularizations.

CONCLUSIONS

In patients with CFVR > 2 of the intermediate nonculprit coronary lesion, deferral of revascularization is safe and associated with excellent long-term clinical outcomes.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Dual imaging stress echocardiography versus computed tomography coronary angiography for risk stratification of patients with chest pain of unknown origin

Background

Dual imaging stress echocardiography, combining the evaluation of wall motion and coronary flow reserve (CFR) on the left anterior descending artery (LAD), and computed tomography coronary angiography (CTCA) are established techniques for assessing prognosis in chest pain patients. In this study we compared the prognostic value of the two methods in a cohort of patients with chest pain having suspected coronary artery disease (CAD).

Methods

A total of 131 patients (76 men; age 68 ± 9 years) with chest pain of unknown origin underwent dipyridamole (up to 0.84 mg/kg over 6 min) stress echo with CFR assessment of LAD by Doppler and CTCA. A CFR ≤ 1.9 was considered abnormal, while > 50% lumen diameter reduction was the criterion for significant CAD at CTCA.

Results

Of 131 patients, 34 (26%) had ischemia at stress echo (new wall motion abnormalities), and 56 (43%) had reduced CFR on LAD. Significant coronary stenosis at CTCA was found in 69 (53%) patients. Forty-six patients (84%) with abnormal CFR on LAD showed significant CAD at CTCA (p < 0.001). Calcium score was higher in patients with reduced than in those with normal CFR (265 ± 404 vs 131 ± 336, p = 0.04). During a median follow-up of 7 months (1st to 3rd quartile: 5–13 months), there were 45 major cardiac events (4 deaths, 11 nonfatal myocardial infarctions, and 30 late [≥6 months] coronary revascularizations). At Cox analysis, independent prognostic indicators were calcium score > 100 (HR 2.84, 95% CI 1.33-6.07, p = 0.007), significant CAD at CTCA (HR 2.68, 95% CI 1.23-5.82, p = 0.013), and inducible ischemia or CFR <1.9R on LAD on dual imaging stress echo (HR 2.25, 95% CI 1.05-4.84, p = 0.038).

Conclusions

Functional and anatomical evaluation using, respectively, dual imaging stress echocardiography and CTCA are both effective modalities to risk stratify patients with chest pain of unknown origin, yielding independent and comparable prognostic value. Compared to CTCA, however, stress echocardiography has the advantage of lower cost and of being free of radiations.

Prognostic value of Doppler echocardiographic-derived coronary flow velocity reserve of left anterior descending artery in octogenarians with stress echocardiography negative for wall motion criteria

AIMS

Doppler-derived coronary flow velocity reserve (CFVR) of left anterior descending (LAD) artery is an effective tool to predict overall mortality. The aim was to investigate the capability of CFVR to predict outcome in an unselected cohort of patients older than 80 years having stress echo negative by wall motion criteria.

METHODS AND RESULTS

The study group refers to 369 patients aged > 80 years (156 men; mean age 83 ± 2 years) who had undergone dipyridamole stress echocardiography with CFVR assessment of LAD artery of known (n = 144) or suspected (n = 225) coronary artery disease. Stress echocardiography was negative for wall motion criteria in all cases. Mean CFVR was 2.07 ± 0.53. During a median follow-up of 21 months, there were 62 major adverse cardiac events (MACEs; 45 deaths and 17 non-fatal myocardial infarctions). With a receiver operating characteristic analysis, a CFVR of ≤ 1.93 was the best cut-off for predicting mortality and MACE. At individual patient analysis, 152 (41%) subjects had a CFVR of < 1.93. Annual mortality was 9.8% in patients with CFVR <1.93 and 3.7% in those with CFVR > 1.93 (P = 0.001); an annual MACE rate was 14.8% in the former and 4.5% in the latter (P < 0.0001). Of 15 clinical and echocardiographic parameters analysed, CFVR ≤ 1.93 [hazard ratio (HR) = 2.17, 95% CI 1.14-4.10] and resting wall motion abnormality (RWMA; HR = 2.60; 95% CI 1.35-5.00) were multivariable indicators of mortality. Moreover, CFVR ≤ 1.93 (HR = 2.69, 95% CI 1.56-4.67), and RWMA (HR = 2.38; 95% CI 1.31-4.33) were also strong independent predictors of MACEs. At incremental analysis, CFR ≤ 1.93 added prognostic information over clinical evaluation and RWMA when both mortality and MACE were taken as clinical end points.

CONCLUSIONS

A reduced CFVR of LAD artery is a strong and independent indicator of both mortality and MACE, adding prognostic information over clinical evaluation and RWMA. Conversely, a preserved CFVR predicts a favourable outcome particularly in subjects with no RWMA.

Detection of coronary artery disease using coronary flow velocity reserve by transthoracic Doppler echocardiography versus multidetector computed tomography coronary angiography: influence of calcium score

BACKGROUND

There have been no clinical data specifying the degree of calcium deposition at which coronary flow velocity reserve (CFVR) measurement using transthoracic Doppler echocardiography surpasses 320-row multidetector computed tomographic coronary angiography (CTCA) in detecting obstructive coronary artery disease.

METHODS

One hundred seventy patients who underwent invasive coronary angiography, transthoracic Doppler echocardiography, and CTCA were prospectively enrolled. Coronary artery stenosis was defined as percentage diameter stenosis ≥ 50% on invasive coronary angiography. CFVR < 2.0 and narrowing ≥ 50% measured with CTCA were the thresholds indicating the presence of coronary artery stenosis. The degree of coronary artery calcification was also assessed using the Agatston calcium score method by computed tomography.

RESULTS

The majority of patients (89%) were classified as having either high or intermediate pretest probability of coronary artery disease. Significant coronary artery stenoses by invasive coronary angiography were found in 71 patients and 104 vessels. Although the overall diagnostic performance of CTCA was comparable with that of CFVR measurement for detecting coronary artery stenosis, only the diagnostic performance of CTCA was negatively affected by the extent of a patient's coronary artery calcification. Receiver operating characteristic curve analysis indicated that only CFVR measurement is diagnostically accurate when calcium scores are >319 in the patient-based assessment, 189 for the left anterior descending coronary artery, 98 for the left circumflex coronary artery and 282 for the right coronary artery.

CONCLUSIONS

Transthoracic Doppler echocardiography and 320-row multidetector CTCA successfully diagnosed significant coronary artery stenosis with high feasibility and accuracy. However, only the diagnostic performance of CTCA was negatively affected by the extent of a patient's coronary artery calcification, and therefore the diagnostic performance of CFVR measurement for detecting coronary artery stenosis surpassed that of CTCA when the calcium score exceeded specified cutoff values.

Prediction of long-term ischemic events by noninvasively assessed coronary flow reserve

BACKGROUND

Coronary flow reserve (CFR) by adenosine echocardiography in left anterior descending (LAD) or posterior descending coronary arteries may predict clinical outcome.

METHODS

We used models accounting (Cox's model) or not (logistic regression and neural network) for time to event and either considered (forced models) or not (stepwise logistic regression and neural network models) all among 21 covariates to predict 1-year composite events after LAD CFR.

RESULTS

There were 553 consecutive patients with coronary artery disease (CAD): 89 patients had also posterior descending CFR. During 1-year follow-up 328 patients were event-free, 35 had composite ischemic events and 190 underwent short-term revascularization. LAD and posterior descending CFR (respectively, 1.53 ± 0.83, N = 225 and 1.84 ± 0.80, N = 42) were significantly (P < 0.0001) lower in patients with events (or with revascularization following CFR measurement) than in those without (respectively, 3.13 ± 0.84, N = 328, and 2.53 ± 0.72, N = 47). Using LAD CFR as a continuous covariate, by both forced Cox's and logistic regression, coefficients (t values, respectively, -14.11 and -10.19) were significant (both P < 0.00001) to predict outcome. Global predictive accuracies by neural network, adopting a receiver operating characteristic areas under the curve (ROC) assessment, were excellent (>0.91) and the role of LAD CFR among predictors was overwhelming. Other indices of myocardial ischemia and the presence of coronary stenoses or previous infarction did not modify the multivariable predictive role of LAD CFR. When patients with revascularization were discounted, the LAD CFR predictive role was the same.

CONCLUSIONS

Thus, adenosine echocardiography-based LAD CFR predicts 1-year composite ischemic events in patients with CAD, independent of the multivariable model adopted. Posterior descending CFR also has a role.

Comparison of coronary flow velocity reserve measurement by transthoracic Doppler echocardiography with 320-row multidetector computed tomographic coronary angiography in the detection of in-stent restenosis in the three major coronary arteries

We sought to compare the diagnostic accuracy and feasibility of coronary flow velocity reserve (CFVR) measurement using transthoracic Doppler echocardiography (TTDE) and 320-row multidetector computed tomographic coronary angiography (CTCA) for predicting in-stent restenosis (ISR). We enrolled 126 consecutive patients with 309 implanted coronary stents in the 3 major coronary arteries. TTDE and CTCA were performed within the 2-week period before follow-up invasive coronary angiography. Binary ISR was defined as percent diameter stenosis ≥50% on invasive coronary angiogram. A CFVR <2.0 using TTDE and a narrowing of ≥50% measured with CTCA were the thresholds indicating the presence of binary ISR. Presence of ISR using invasive coronary angiography was observed in 26 (8%) stents and 26 (14%) vessels. Feasibilities of CFVR measurement and CTCA for predicting ISR in the 3 major vessels were 94% and 91%, respectively. A CFVR <2.0 revealed a 95% diagnostic accuracy with sensitivity of 87%, specificity of 96%, positive predictive value of 77%, and negative predictive value of 98%. Diagnostic accuracy of CTCA was comparable to that of CFVR measurement; however, CTC angiographic results were confounded by metal artifacts in the assessment of small-diameter stents. In conclusion, noninvasive CFVR measurement has high feasibility and accuracy for predicting ISR and is comparable to 320-row CTCA.

Disproportionally impaired microvascular structure in essential hypertension

BACKGROUND

Increased microvascular resistance and small artery remodelling are key abnormalities in the pathophysiology of essential hypertension. We investigated the relation between the impairment of coronary and forearm minimum vascular resistances (C-Rmin and F-Rmin) and the degree of hypertension.

METHOD

Seventy-five never-treated essential hypertension patients with 24-h systolic blood pressure (BP) at least 130 mmHg or diastolic BP at least 80 mmHg were assigned into grade 1 (office BP 140/90-159/99 mmHg) and grade 2 (office BP 160/100-179/109 mmHg) hypertension and compared to normotensive controls (n = 25). The patients were (48 years, 60% men) without cardiovascular disease. C-Rmin and coronary flow reserve (CFR) were derived from flow measurements in the left anterior descending artery using transthoracic echocardiography. F-Rmin was measured using venous occlusion plethysmography. Resting systemic vascular resistance index (SVRI) was measured with a gas rebreathing technique.

RESULTS

Compared to normotensive controls: 24-h mean BP was raised 14% in grade 1 essential hypertension and 28% in grade 2 essential hypertension, whereas F-Rmin and C-Rmin were elevated by 58 and 87% in grade 1 essential hypertension and 72 and 125% in grade 2 essential hypertension. C-Rmin and F-Rmin were thus both increased more than expected from the BP level. SVRI and left-ventricular mass were increased proportionally to the BP. CFR was decreased by approximately 30% in both essential hypertension groups.

CONCLUSION

The results demonstrate excessive microvascular structural abnormalities in hypertension suggesting microvascular alterations occur early and not just as an adaptation to the BP level. Thus the level of BP elevation does not give an accurate indication of the microvascular involvement and impairment in essential hypertension.

Prognostic effect of coronary flow reserve in women versus men with chest pain syndrome and normal dipyridamole stress echocardiography

The aim of this study was to investigate the prognostic effect of coronary flow reserve (CFR) on left anterior descending artery (LAD) in women and men with chest pain of unknown origin and normal stress echocardiogram. The study population consisted of 1,660 patients (906 women, 754 men) with chest pain syndrome, no wall motion abnormality on echocardiogram at rest, and dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiogram negative for wall motion criteria. All had undergone stress echocardiography with combined evaluation of CFR on LAD by Doppler. A CFR value ≤2.0 was considered abnormal. Median duration of follow-up was 19 months (interquartile range 10 to 34). Abnormal CFR was assessed in 171 women (19%) and 147 men (19%, p = 0.80). During follow-up, 80 events (20 deaths, 13 ST-elevation myocardial infarctions, and 47 non-ST-elevation myocardial infarctions) occurred. In addition, 128 patients underwent revascularization and were censored. CFR ≤2.0 on LAD was independently associated with prognosis in women (hazard ratio [HR] 16.48, 95% confidence interval [CI] 7.17 to 37.85, p <0.0001) and in men (HR 6.23, 95% CI 3.42 to 11.33, p <0.0001). Antianginal therapy at time of testing (HR 2.11, 95% CI 1.14 to 3.90, p = 0.02) was also a multivariable prognostic predictor in men. Four-year event rate associated with CFR values ≤2.0 and >2.0 were, respectively, 27% and 2% in women (p <0.0001) and 42% and 8% in men (p <0.0001). In conclusion, decreased CFR on LAD is associated with markedly increased risk in women and men with chest pain syndrome and a normal result of dipyridamole stress echocardiography. Conversely, preserved CFR on LAD predicts excellent survival, particularly in women.

Long-term prognostic value of coronary flow reserve in patients without significant left anterior descending coronary artery stenosis: results from the SZEGED Study

A coronariaáramlási rezerv (CFR) a bal coronaria leszálló szárában (LAD) szignifikáns szűkület hiánya esetén a microvascularis (disz)funkció jellemzésére használható hemodinamikai index. Célkitűzés: Jelen tanulmány célja a LAD-ban mért CFR prognosztikus értékének tisztázása lenne, amennyiben a koronarográfia során a LAD-ban szignifikáns szűkület nem volt igazolható. Módszerek: A jelen tanulmányban 166 olyan beteg eredményeit elemeztük, akiknél a CFR-vizsgálatok idején elvégzett koronarográfia a LAD-ban szignifikáns szűkületet (>50%) nem mutatott ki. Valamennyi esetben transthoracalis és terheléses transoesophagealis echokardiográfia (CFR-mérés), valamint koronarográfia történt. Eredmények: A továbbkövetés átlagos ideje 93±34 hónap volt, sikeressége 75%-osnak bizonyult (124/166). A továbbkövetés időszaka alatt 27 beteg hunyt el, 16 beteg esetén hirtelen szívhalál, 3 esetben akut szívelégtelenség, 2 esetben stroke volt a halál oka, míg 6 beteg pulmonalis, illetve gastrointestinalis tumoros folyamat miatt halt meg. A ROC-analízis során a CFR ≥ 2,13-t találtuk a legnagyobb pontosságú cut-off (határ-) értéknek a túlélés előrejelzésében (szenzitivitás 67%, specificitás 60%, görbe alatti terület 62%, p = 0,046). A 2,13-nál alacsonyabb CFR-rel bíró betegekben a továbbkövetés során szignifikánsan több esemény történt, mint az annál nagyobb értékkel bíróknál (32% vs. 13%, p < 0,05). A multivariáns logisztikus regressziós modell során a CFR [hazard ratio (HR) 2,43, p = 0,04] és a bal kamrai végszisztolés térfogatérték [HR 1,49, p = 0,03] bizonyult a túlélés független prediktorának. Következtetések: Hosszú távú továbbkövetéses vizsgálataink alapján megállapíthatjuk, hogy a CFR a túlélés független prediktora a LAD szignifikáns szűkületét nem mutató betegekben.

Implication of the continuous prognostic spectrum of Doppler echocardiographic derived coronary flow reserve on left anterior descending artery

The additive prognostic value of coronary flow reserve (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. We assessed the prognostic value of quartiles of CFR, evaluated by transthoracic Doppler of the left anterior descending coronary artery (LAD), in patients with known or suspected coronary artery disease (CAD). One thousand six hundred twenty patients (1,006 men, 64 +/- 11 years of age) underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiography with CFR evaluation of LAD by Doppler and coronary angiography. Patients were followed up for a median of 19 months. Mean CFR in the entire population was 2.25 +/- 0.65. Stress echocardiogram was positive for ischemia in 480 patients (30%). Obstructive (>or=70% vessel stenosis) CAD at angiography was present in 650 patients (40%). During follow-up, there were 298 events (42 deaths, 73 ST-elevation myocardial infarctions, and 183 non-ST-elevation myocardial infarctions). Patients (n = 399) undergoing revascularization were censored. With the Kaplan-Meier method, the first quartile of CFR (<or=1.80) was associated with a worse (p <0.0001) event rate than other quartiles in the entire population and in patients with no ischemia at stress echocardiography. Furthermore, the second quartile of CFR (1.81 to 2.16) was predictive of increased (p <0.0001) risk compared to the higher quartiles. In conclusion, Doppler echocardiographically derived CFR in LAD is a strong and independent prognostic predictor in patients with known or suspected CAD, but the spectrum of prognostic stratifications is expanded if the response is titrated according to a continuous scale rather than artificially dichotomized.