Intermediate-grade Stenosis Research Articles

Invasive fractional-flow-reserve prediction by coronary CT angiography using artificial intelligence vs. computational fluid dynamics software in intermediate-grade stenosis

Coronary computed angiography (CCTA) with non-invasive fractional flow reserve (FFR) calculates lesion-specific ischemia when compared with invasive FFR and can be considered for patients with stable chest pain and intermediate-grade stenoses according to recent guidelines. The objective of this study was to compare a new CCTA-based artificial-intelligence deep-learning model for FFR prediction (FFRAI) to computational fluid dynamics CT-derived FFR (FFRCT) in patients with intermediate-grade coronary stenoses with FFR as reference standard. The FFRAI model was trained with curved multiplanar-reconstruction CCTA images of 500 stenotic vessels in 413 patients, using FFR measurements as the ground truth. We included 37 patients with 39 intermediate-grade stenoses on CCTA and invasive coronary angiography, and with FFRCT and FFR measurements in this retrospective proof of concept study. FFRAI was compared with FFRCT regarding the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for predicting FFR ≤ 0.80. Sensitivity, specificity, PPV, NPV, and diagnostic accuracy of FFRAI in predicting FFR ≤ 0.80 were 91% (10/11), 82% (23/28), 67% (10/15), 96% (23/24), and 85% (33/39), respectively. Corresponding values for FFRCT were 82% (9/11), 75% (21/28), 56% (9/16), 91% (21/23), and 77% (30/39), respectively. Diagnostic accuracy did not differ significantly between FFRAI and FFRCT (p = 0.12). FFRAI performed similarly to FFRCT for predicting intermediate-grade coronary stenoses with FFR ≤ 0.80. These findings suggest FFRAI as a potential non-invasive imaging tool for guiding therapeutic management in these stenoses.

Comprehensive Assessment of Myocardial Ischemia Mechanisms in the Catheterization Laboratory: Design and Rationale of the Advanced Invasive Diagnosis Strategy for Patients with Stable Coronary Syndromes Undergoing Coronary ANGIOgraphy - the AID-ANGIO Study

BackgroundThe diagnostic yield of invasive coronary angiography (ICA) to identify obstructive coronary artery disease in the context of chronic coronary syndromes (CCS) is very low. Furthermore, myocardial ischemia may have a non-obstructive origin, which cannot be detected by ICA. MethodsAID-ANGIO is an observational, prospective, single-cohort, multicenter study, intended to evaluate the diagnostic yield of adopting a hierarchical strategy to assess obstructive and non-obstructive causes of myocardial ischemia in an all-comers population of patients with CCS at the time of ICA. The primary endpoint will investigate the additional diagnostic value of such strategy over angiography alone regarding the identification of ischemia-generating mechanisms. SummaryAn estimated sample of consecutive 260 patients with CCS referred by their clinicians to ICA, will be enrolled. In a stepwise manner, a conventional ICA will be performed as the initial diagnostic tool. Those patients with severe-grade stenosis will not undergo further assessment and an obstructive origin for myocardial ischemia will be assumed. Subsequently, the remainder with intermediate-grade stenosis will be assessed with pressure guidewires. Those with a negative result from physiological evaluation and those without epicardial coronary stenosis will be further studied for ischemia of non-obstructive origin, including microvascular dysfunction and vasomotor disorders.The study will be conducted in two steps. Firstly, ICA images will be displayed to patient's referring clinicians, who will be asked to identify the existent epicardial stenosis, their angiographic severity and probable physiological relevance, together with a tentative therapeutic approach. Then, the diagnostic algorithm will continue to be applied and, considering the whole gathered information, a definite therapeutic plan will be consensually established by the interventional cardiologist and patient's referring clinicians. ConclusionThe AID-ANGIO study will assess the additional diagnostic yield of a hierarchical strategy over ICA alone to identify ischemia-generating mechanisms in patients with CCS and its impact on therapeutic approach. Positive results of the study might support a streamlined invasive diagnostic process for patients with CCS.

Plasma Homocysteine in Patients with Coronary and Carotid Artery Disease: A Case Control Study.

Homocystein (Hcy) is an amino acid and elevated plasma cause endothelial damage, followed with inflammation in the blood vessels and its progression in atherosclerosis. We aimed to evaluate the correlation between cardiovascular disease and serum homocysteine levels.. We performed a case control analysis of 212 patients, either for cardiovascular risk stratification or for invasive diagnostics and treatment of cardiovascular ischemic disease (CAD). Patients were divided into 4 groups: Group 1. Patients with low risk for CAD, with no symptoms of CAD and total of 10 years risk <10%. Group 2. High-risk patients with no symptoms of CAD, but 10 years total CAD risk of >20%. Group 3. Patients with symptomatic CAD, where angiography was performed and >50% occlusion of at least one coronary vessel was found. Group 4. Patients with carotid artery disease and documented CAD. Group 1 consists of 56 subjects, of whom 33 (60%) males and 22 (40%) females. Their mean age was 52.18±8.07 years and their average CAD risk was 5. Group 2 included 60 patients, with average CAD risk of 23.73. There was a statistically significant difference between plasma homocysteine levels between the control and high CAD risk group, as well as between those with CAD and both CAD and CARD (p=0.001). In the high-risk subjects group, the level of homocysteine correlates albeit weak with the total CAD risk (p=0.04). Homocysteine levels correlate with the WBC count (p=0.02). In the subgroup of smokers with high CAD risk, homocysteine correlates with age, total CAD risk, total cholesterol, BUN (define BUN) and creatinine. Group 3 consisted of 49 subjects with manifested and angiographically proven CAD, out of whom 80% were males and 20% females, mean age 56.06±9.7 years, with average 2 coronary vessels affected. There were significantly higher homocysteine plasma levels between the control group and the group with manifested CAD (p=0.008).There is no significant difference of homocysteine plasma levels between the high risk group and the group with manifested coronary artery disease (15.03□mol/l vs. 16.38□mol/l). In this group, plasma levels of homocysteine correlate only with the highest level of vessel stenosis (>95%) with (p=0.04). The study population in group 4 showed a mean of IMT 0.9 +..09 mm and mean Hcy plasma levels of 21 + 11 µmol/L. From the evaluated patients with CAD, 82.9% of patients had elevated level of Hcy. From those, one showed elevated Hcy, 79.4 % had hypertension, 58.9 % had hyperlipidemia, 28.2% had diabetes mellitus as additional risk factors for atherosclerosis. 76.9 % of the patients had increased intima-media thickness; in 58.9 % plaques were detected, while 23 % of the patients had significant stenosis: 10.2 % with intermediate-grade stenosis (50-69%) and 12.8 % with high-grade stenosis (70-99 %). 17.1 % of the patients had normal level of Hcy, and in those ones 62.5 % only had increased IMT. We found linear correlation between IMT and HCy levels (r 0.7, p 0.05). Case control analysis showed significant higher level of Hcy in the group with CAD and carotid artery disease vs. CAD group (p 0.001). High plasma homocysteine concentrations are associated with high risk for vascular disease and consequently CAD itself and carotid artery disease, as well, proving its likely role in the development of atherosclerosis on inflammatory and metabolic levels.

Correlation of FFR-derived from CT and stress perfusion CMR with invasive FFR in intermediate-grade coronary artery stenosis

Only one-third of intermediate-grade coronary artery stenosis (i.e. 40-70% diameter narrowing) causes myocardial ischemia, requiring most often additional invasive work-up with invasive fractional flow reserve (FFR). To evaluate the correlations between FFR estimates derived from computed tomography (FFRCT) and adenosine perfusion cardiac magnetic resonance (CMR) with invasive FFR in intermediate-grade stenosis. Thirty-seven patients (mean age 61 ± 9 years; 25 men) who underwent adenosine perfusion CMR, quantitative coronary angiography and FFR in the work-up for intermediate-grade stenoses (n = 39) diagnosed at coronary CT angiography were retrospectively evaluated. Blinded FFRCT analysis was computed on each intermediate-grade lesion and correlated to the FFR values. On adenosine CMR, subendocardial time-enhancement maximal upslopes, normalized by respective left ventricle cavity upslopes, were obtained distal to a coronary stenosis (RISK area) and in remote myocardium (REMOTE area). The perfusion was subsequently assessed without (uncorrected RISK) and after correction for remote perfusion (relative myocardial perfusion index = REMOTE/RISK ratio), and then correlated to the FFR values. Differences in correlations were tested with z statistics and considered statistically significant different at a p < 0.05 level. The average FFR value was 0.85 ± 0.10 (0.60-0.98 range), 28% (n = 11) was ≤ 0.80. FFR value correlated poorly with uncorrected RISK upslopes (r = 0.151; p = 0.36), but equally strongly with FFRCT (r = 0.675; p < 0.001) and the relative myocardial perfusion index (r = - 0.63) (p < 0.001; z = 6.72) for assessment of lesion-specific ischemia. Both FFRCT and adenosine perfusion CMR strongly correlate with invasive FFR measurements for intermediate-grade stenosis. These preliminary findings pave the way for further studies evaluating non-invasively intermediate coronary stenosis in clinical practice.

Fusion of Three-Dimensional Echocardiographic Regional Myocardial Strain with Cardiac Computed Tomography for Noninvasive Evaluation of the Hemodynamic Impact of Coronary Stenosis in Patients with Chest Pain

Combined evaluation of coronary stenosis and the extent of ischemia is essential in patients with chest pain. Intermediate-grade stenosis on computed tomographic coronary angiography (CTCA) frequently triggers downstream nuclear stress testing. Alternative approaches without stress and/or radiation may have important implications. Myocardial strain measured from echocardiographic images can be used to detect subclinical dysfunction. The authors recently tested the feasibility of fusion of three-dimensional (3D) echocardiography-derived regional resting longitudinal strain with coronary arteries from CTCA to determine the hemodynamic significance of stenosis. The aim of the present study was to validate this approach against accepted reference techniques. Seventy-eight patients with chest pain referred for CTCA who also underwent 3D echocardiography and regadenoson stress computed tomography were prospectively studied. Left ventricular longitudinal strain data (TomTec) were used to generate fused 3D displays and detect resting strain abnormalities (RSAs) in each coronary territory. Computed tomographic coronary angiographic images were interpreted for the presence and severity of stenosis. Fused 3D displays of subendocardial x-ray attenuation were created to detect stress perfusion defects (SPDs). In patients with stenosis >25% in at least one artery, fractional flow reserve was quantified (HeartFlow). RSA as a marker of significant stenosis was validated against two different combined references: stenosis >50% on CTCA and SPDs seen in the same territory (reference standard A) and fractional flow reserve<0.80 and SPDs in the same territory (reference standard B). Of the 99 arteries with no stenosis >50% and no SPDs, considered as normal, 19 (19%) had RSAs. Conversely, with stenosis >50% and SPDs, RSAs were considerably more frequent (17 of 24 [71%]). The sensitivity, specificity, and accuracy of RSA were 0.71, 0.81, and 0.79, respectively, against reference standard A and 0.83, 0.81, and 0.82 against reference standard B. Fusion of CTCA and 3D echocardiography-derived resting myocardial strain provides combined displays, which may be useful in determination of the hemodynamic or functional impact of coronary abnormalities, without additional ionizing radiation or stress testing.

Coronary artery plaque characterization using MDCT in symptomatic and asymptomatic subgroups of diabetic and non-diabetic population-a comparative retrospective study.

The study was designed with the aims to evaluate the use of multidetector CT (MDCT) in coronary plaque detection and characterization in diabetic and non-diabetic subjects. Further, to compare the plaque morphology and composition in diabetic and non-diabetic patients in both symptomatic and asymptomatic subgroups. We performed CT coronary angiography (CTCA) of 100 patients, out of which 50 had type II diabetes and further subdivided into symptomatic and asymptomatic groups. For every patient, we mapped the disease with different grades of coronary artery disease (CAD), the number of plaques, and histological types of plaques, as well as different atherosclerotic scores were derived to assess the severity and extent of CAD. The total number of assessable segments was 1410 (96%). The symptomatic diabetic patient had a higher prevalence of significant CAD. Coronary, atherosclerotic, and extent scores showed significant difference in diabetic patients as compared to non-diabetic (p < 0.0181, < 0.0125, < 0.0043) whereas severity score was insignificant (p < 0.0627). There was a significant difference in all the scores in symptomatic diabetic and symptomatic non-diabetic subgroups. Further, no difference was observed in the asymptomatic subgroup. Diabetic patients harbor twice the plaque volume as compared to non-diabetic. Vulnerable plaques were more prevalent in asymptomatic patients with intermediate grade stenosis. CTCA plays a pivotal role in the risk stratification. Diabetic patients were found have intermediate grade stenosis and higher load of both stable and vulnerable plaques than non-diabetics. Furthermore, the percentage of vulnerable plaque was higher in asymptomatic group as compared to symptomatic patients.

Rationale, design and goals of the HeartFlow assessing diagnostic value of non-invasive FFRCT in Coronary Care (ADVANCE) registry

BackgroundCoronary CT angiography (CTA) is a reliable tool for the detection of coronary artery disease (CAD) that conveys significant prognostic information. It does not provide data on the hemodynamic significance of a given lesion, particularly in intermediate-grade stenosis. Fractional flow reserve by CT (FFRCT) can accurately predict the hemodynamic significance of coronary lesions. The primary objective of this registry is to determine whether the integration of FFRCT as an adjunct to coronary CTA will lead to a significant change in the management of CAD in patients with stable angina. MethodsThe ADVANCE Registry is a multi-center, prospective registry designed to evaluate utility, clinical outcomes and resource utilization following FFRCT-guided treatment in clinically stable, symptomatic patients diagnosed with CAD by coronary CTA. Approximately 5000 patients will be enrolled from up to 50 sites in Europe, USA, Canada and Asia. Requirement for enrollment is the presence of atherosclerosis on coronary CTA. For each enrolled patient, a clinical management review committee will use data from coronary CTA and FFRCT to determine the management plan using the following criteria: (a) optimal medical therapy, (b) percutaneous coronary intervention, (c) coronary artery bypass graft surgery, or (d) more information required. The primary endpoint of the registry is the reclassification rate between the management plan based on coronary CTA alone versus CTA plus FFRCT. The secondary endpoints of the registry include the evaluation of the rate of invasive coronary angiography (ICA), revascularization, major adverse coronary events, resource utilization, cumulative radiation dose exposure and the rate of ICA without obstructive CAD at 3-year follow-up. ConclusionsThe ADVANCE registry is designed to assess the real-world impact of FFRCT on the clinical management of stable CAD when used along with coronary CTA.

Myocardial perfusion imaging with a cadmium zinc telluride-based gamma camera versus invasive fractional flow reserve

Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥ 0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization.

Long-term internal thoracic artery bypass graft patency and geometry assessed by multidetector computed tomography

The left internal thoracic artery (LITA) undergoes vascular remodelling when used for coronary artery bypass grafting. In this study we tested the hypothesis that the extent of the LITA remodelling late after coronary artery bypass grafting assessed by multidetector computed tomography is related to the severity of stenosis in the native coronary vessel. One hundred and forty-two patients who had undergone coronary artery bypass grafting including implantation of LITA as conduit to the left anterior descending artery were studied 5 years after surgery. Arterial graft patency and geometry was assessed with 64-slice multidetector computed tomography. Quantitative volumetric assessment of the LITA was performed to measure the average vessel lumen area (mm(2)/m(2)). The native coronary vessel subtended by the LITA was evaluated by multidetector computed tomography and defined as a high-grade stenosis patient group, when the diameter stenosis was >70% and an intermediate grade stenosis patient group when <70%. Among patients with intermediate-grade stenosis of the native vessel 11 out of 65 patients (17%) had a totally occluded LITA, as opposed to none among the 77 patients with a high-grade stenosis. In patients with intermediate-grade stenosis of the proximal native vessel, the LITA lumen area was 4.9 compared to 5.3 mm(2)/m(2) in patients with a high-grade stenosis of the proximal native vessel (P = 0.0043). Lumen area of the LITA when used as a conduit in patients with coronary artery disease seems to be inversely correlated with the severity of disease in the native coronary vessel proximal to the anastomosis. Volumetric vessel multidetector computed tomography appears to be useful for evaluation of coronary bypass remodelling.

Value of Cardiovascular Magnetic Resonance Stress Perfusion Testing for the Detection of Coronary Artery Disease in Women

We wanted to assess the value of cardiovascular magnetic resonance (CMR) stress testing for evaluation of women with suspected coronary artery disease (CAD). A combined perfusion and infarction CMR examination can accurately diagnose CAD in the clinical setting in a mixed gender population. We prospectively enrolled 147 consecutive women with chest pain or other symptoms suggestive of CAD at 2 centers (Duke University Medical Center, Robert-Bosch-Krankenhaus). Each patient underwent a comprehensive clinical evaluation, a CMR stress test consisting of cine rest function, adenosine-stress and rest perfusion, and delayed-enhancement CMR infarction imaging, and X-ray coronary angiography within 24 h. The components of the CMR test were analyzed visually both in isolation and combined using a pre-specified algorithm. Coronary artery disease was defined as stenosis > or =70% on quantitative analysis of coronary angiography. Cardiovascular magnetic resonance imaging was completed in 136 females (63.0 +/- 11.1 years), 37 (27%) women had CAD on coronary angiography. The combined CMR stress test had a sensitivity, specificity, and accuracy of 84%, 88%, and 87%, respectively, for the diagnosis of CAD. Diagnostic accuracy was high at both sites (Duke University Medical Center 82%, Robert-Bosch-Krankenhaus 90%; p = 0.18). The accuracy for the detection of CAD was reduced when intermediate grade stenoses were included (82% vs. 87%; p = 0.01 compared the cutoff of stenosis > or =50% vs. > or =70%). The sensitivity was lower in women with single-vessel disease (71% vs. 100%; p = 0.06 compared with multivessel disease) and small left ventricular mass (69% vs. 95%; p = 0.04 for left ventricular mass < or =97 g vs. >97 g). The latter difference was even more significant after accounting for end-diastolic volumes (70% vs. 100%; p = 0.02 for left ventricular mass indexed to end-diastolic volume < or =1.15 g/ml vs. >1.15 g/ml). A multicomponent CMR stress test can accurately diagnose CAD in women. Detection of CAD in women with intermediate grade stenosis, single-vessel disease, and with small hearts is challenging.

A change in the pattern of vasospasm after stenting in a patient with vasospastic angina

We report an unusual case of a male patient with vasospastic angina in whom the pattern of coronary artery spasm changed after coronary stenting. The patient was admitted to our hospital with an acute coronary syndrome. Coronary angiography revealed an intermediate grade stenosis in the right coronary artery, and focal coronary spasm was provoked by intracoronary acetylcholine. A diagnosis of vasospastic angina was made, and the patient was followed medically. He subsequently was readmitted with refractory vasospastic angina and underwent coronary stenting. He was pain-free after stent implantation. Repeat angiography 6 months later showed no restenosis in the stented segment; however, coronary spasm was provoked in all areas except the stented segment by intracoronary acetylcholine injection.

Surgical Referral for Carotid Artery Stenosis — The Influence of NASCET

A retrospective review was undertaken of 139 consecutive patients with presumed carotid artery stenosis referred to a vascular neurosurgeon. The review period included three years prior and one year subsequent to the publication of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) preliminary results showing surgery to be superior to best medical therapy for patients with symptomatic, high grade (> 70% linear diameter) carotid stenosis. The aims of this analysis were to determine any changes in the referral pattern following the NASCET publication (post-NASCET), and to examine the use and reliability for surgical decision making of pre-referral carotid artery imaging. Patient referral rate increased markedly post-NASCET, particularly from neurologists. There was a trend for more post-NASCET referrals to be for high grade stenosis and fewer referrals to be for intermediate grade (30-69% linear diameter) stenosis, although continued referral of patients with intermediate grade stenosis is desirable as randomization into NASCET continues for this group of patients. Ninety-six patients (69%) were referred with carotid duplex ultrasonography having been performed. There was poor correlation of these results with angiography, which remains necessary for planning management. A majority of patients (65%) referred to this surgical practice did not come to surgery.