The association of epicardial fat volume with coronary characteristics and clinical outcome.

Recent studies have demonstrated the relationship between epicardial fat volume (EFV) and coronary atherosclerosis, but their association is modest at best. Our purpose is to elucidate the association of epicardial fat with coronary characteristics and clinical outcome. We performed coronary computed tomographic angiography in 651 patients and divided them into three groups according to tertiles of EFV; low-tertile (n = 215), 36-123 ml; middle-tertile (n = 218), 124-165 ml; high-tertile (n = 218), 166-489 ml. The prevalence of coronary calcium score (CCS) >0 (71.6, 73.4, and 83.9% in low-, middle-, and high-tertile group, respectively) and CCS >100 (39.1, 39.9, and 59.2% in each group) was significantly higher in patients with high-tertile EFV compared to the other two groups (p = 0.0047 and p < 0.0001, respectively). The prevalence of CCS >400 was 17.2, 25.7, and 33.1% in each group, which increased stepwise as EFV increased. The significant stenosis (36.2 vs. 27.0%, p = 0.0383), total coronary occlusion (5.5 vs. 0.9%, p = 0.0156), and high-risk plaque (11.0 vs. 5.6%, p = 0.0368) were more prevalent in patients with high-tertile EFV compared to those with low-tertile EFV. The combined rate of cardiac death and myocardial infarction was 0.9, 2.3, and 6.4% in each patient group, respectively, which was significantly higher in patients with high-tertile EFV compared to those with low-tertile EFV (p = 0.0004). The prevalence of coronary artery calcium, significant stenosis, and high-risk plaque increased sharply in patients with high EFV, which was associated with higher rate of cardiac death and myocardial infarction. Thus, high EFV was associated with advanced coronary atherosclerosis and poor prognosis.

Relationship between coronary calcium score and high-risk plaque/significant stenosis.

AIM: To investigate the relationship between coronary calcium score (CCS) and vulnerable plaque/significant stenosis using coronary computed tomographic angiography (CCTA). METHODS: CCTA was performed in 651 patients and these patients were divided into the four groups (CCS 0, 1-100, 101-400 and > 400). We studied the incidence of high-risk plaque, including positive remodeling, low attenuation plaque, spotty calcification, and napkin-ring sign, and significant stenosis in each group. RESULTS: High-risk plaque was found in 1.3%, 10.1%, 13.3% and 13.4% of patients with CCS 0, 1-100, 101-400 and > 400, respectively (P < 0.001). The difference was only significant for patients with zero CCS. The incidence of significant stenosis was 0.6%, 7.6%, 13.3% and 26.9% for each patient group, respectively (P < 0.001), which represented a significant stepwise increase as CCS increased. The combined incidence of high-risk plaque and significant stenosis was 1.9%, 17.7%, 26.9% and 40.3% in each patient group, respectively (P < 0.001), again representing a significant stepwise increase with CCS. The rate of major coronary event was 0%, 4.0%, 7.9% and 17.2% in each patient group, respectively (P < 0.001), another significant stepwise increase as CCS increased. CONCLUSION: Stepwise increased risk of coronary events associated with increasing CCS is caused by increasing incidence of significant stenosis, while that of high-risk plaque remains the same.

Dynamic change of high-risk plaque detected by coronary computed tomographic angiography in patients with subclinical coronary artery disease.

We studied the dynamic change of high-risk plaque detected by coronary computed tomographic angiography (CCTA) in patients with subclinical coronary artery disease. We analyzed paired CCTA findings in 103 patients. The follow-up period was 1.37 ± 0.49 years. We studied the prevalence and change of high-risk plaque (HRP) defined as positive remodeling, low attenuation plaque, spotty calcification, or napkin-ring sign. Of 413 plaques detected by CCTA, thirty-seven patients had 47 HRP at baseline. At follow-up, eight patients showed disappearance of HRP. Sixty-six patients had no HRP at baseline. At follow-up, new HRP was detected in 12 patients. As a whole, 20 patients (19.4 %) showed appearance or disappearance of HRP. For 29 patients with persistent HRP, five of twenty-one patients with one HRP at baseline showed two HRP at follow-up. Five of eight patients with two HRP at baseline showed one HRP at follow-up. As a whole, in 27 % of patients with persistent HRP, the number of HRP changed. These changes were neither associated with statin use nor location of the HRP. Our results showed that about 20 % of patients showed appearance or disappearance of HRP 1 year later. In addition, in 27 % of patients with persistent HRP, the number of HRP increased or decreased. These results suggest a dynamic nature of HRP.

Potential Utility of Multidetector Computed Tomography to Identify both Cardiac Embolic Sources and Coronary Artery Disease in Patients with Embolic Stroke.

OBJECTIVES: Our objective was to study the potential utility of multidetector computed tomography (MDCT) to identify both cardiac embolic sources and coronary artery disease (CAD) in embolic-stroke patients. METHODS: We performed MDCT for 184 patients with embolic stroke but without known CAD. Twenty-six patients had atrial fibrillation. We investigated the prevalence of the potential source of the embolism and the coronary characteristics. RESULTS: Overall, 64 potential embolic sources were detected in 59 patients (32.1%). Left atrial appendage thrombus, left ventricular thrombus and aortic atheroma were detected in 3.3, 0.5 and 15.8% of patients, respectively. Circulatory stasis and patent foramen ovale were detected in 8.7 and 6.5%, respectively. As for coronary calcium score, only 47 patients (25.5%) had a score of zero and 51 (27.7%) had a score of ≥ 400. Significant CAD was detected in 18 patients (9.8%). One hundred and thirty-seven (74.5%) had coronary plaques. The prevalence of positive remodeling, low-attenuation plaque, spotty calcification and a napkin-ring sign was 7.1, 1.6, 5.4 and 2.7%, respectively. Importantly, only 34 patients (13.0%) had no abnormalities detected by MDCT. CONCLUSIONS: Our results suggest that MDCT has potential to identify both cardiac embolic sources and CAD in patients with embolic stroke but without known CAD.

Prevalence of subclinical coronary artery disease in ischemic stroke patients.

BACKGROUND: Recently, ischemic stroke has emerged as a new coronary artery disease (CAD) risk equivalent. Our purpose is to study the prevalence of CAD in ischemic stroke patients compared with that in non-stroke patients. METHODS AND RESULTS: We measured coronary calcium score (CCS) in 151 ischemic stroke patients without known CAD (stroke group) and compared it with 151 age- and sex-matched non-stroke patients (control group). CCS was significantly higher in the stroke group than in the control group (stroke group, median: 64, interquartile range: 3-382 vs. control group, median: 3, interquartile range: 0-65, p<0.0001). High-risk CAD, defined as a CCS≥400, was detected in 24.5% of the stroke group compared with 9.3% of the control group (p<0.0001). Agreement between the Framingham risk score and CCS was found in only 62 patients (41.1%). In a multiple logistic regression analysis, age [hazard ratio (HR) 1.09, 95% confidence interval (CI) 1.03-1.14], diabetes (HR 2.97, 95%CI 1.52-5.78), stroke (HR 3.85, 95%CI 1.89-7.81), and male sex (HR 4.41, 95%CI 1.82-0.75) were significantly associated with high-risk CAD (p<0.001). CONCLUSIONS: Our results show that the prevalence of subclinical CAD in ischemic stroke patients was high, and that a quarter of them had high-risk CAD. Age, diabetes, stroke, and male sex were independent predictors of high-risk CAD.

Prognostic value of fractional flow reserve: linking physiologic severity to clinical outcomes.

BACKGROUND: Fractional flow reserve (FFR) has become an established tool for guiding treatment, but its graded relationship to clinical outcomes as modulated by medical therapy versus revascularization remains unclear. OBJECTIVES: The study hypothesized that FFR displays a continuous relationship between its numeric value and prognosis, such that lower FFR values confer a higher risk and therefore receive larger absolute benefits from revascularization. METHODS: Meta-analysis of study- and patient-level data investigated prognosis after FFR measurement. An interaction term between FFR and revascularization status allowed for an outcomes-based threshold. RESULTS: A total of 9,173 (study-level) and 6,961 (patient-level) lesions were included with a median follow-up of 16 and 14 months, respectively. Clinical events increased as FFR decreased, and revascularization showed larger net benefit for lower baseline FFR values. Outcomes-derived FFR thresholds generally occurred around the range 0.75 to 0.80, although limited due to confounding by indication. FFR measured immediately after stenting also showed an inverse relationship with prognosis (hazard ratio: 0.86, 95% confidence interval: 0.80 to 0.93; p < 0.001). An FFR-assisted strategy led to revascularization roughly half as often as an anatomy-based strategy, but with 20% fewer adverse events and 10% better angina relief. CONCLUSIONS: FFR demonstrates a continuous and independent relationship with subsequent outcomes, modulated by medical therapy versus revascularization. Lesions with lower FFR values receive larger absolute benefits from revascularization. Measurement of FFR immediately after stenting also shows an inverse gradient of risk, likely from residual diffuse disease. An FFR-guided revascularization strategy significantly reduces events and increases freedom from angina with fewer procedures than an anatomy-based strategy.

Myocardial ischemia is a key factor in the management of stable coronary artery disease.

Previous studies demonstrated that coronary revascularization, especially percutaneous coronary intervention (PCI), does not significantly decrease the incidence of cardiac death or myocardial infarction in patients with stable coronary artery disease. Many studies using myocardial perfusion imaging (MPI) showed that, for patients with moderate to severe ischemia, revascularization is the preferred therapy for survival benefit, whereas for patients with no to mild ischemia, medical therapy is the main choice, and revascularization is associated with increased mortality. There is some evidence that revascularization in patients with no or mild ischemia is likely to result in worsened ischemia, which is associated with increased mortality. Studies using fractional flow reserve (FFR) demonstrate that ischemia-guided PCI is superior to angiography-guided PCI, and the presence of ischemia is the key to decision-making for PCI. Complementary use of noninvasive MPI and invasive FFR would be important to compensate for each method's limitations. Recent studies of appropriateness criteria showed that, although PCI in the acute setting and coronary bypass surgery are properly performed in most patients, PCI in the non-acute setting is often inappropriate, and stress testing to identify myocardial ischemia is performed in less than half of patients. Also, some studies suggested that revascularization in an inappropriate setting is not associated with improved prognosis. Taken together, the presence and the extent of myocardial ischemia is a key factor in the management of patients with stable coronary artery disease, and coronary revascularization in the absence of myocardial ischemia is associated with worsened prognosis.

Myocardial perfusion defect in patients with coronary artery disease demonstrated by 64-multidetector computed tomography at rest.

BACKGROUND: The first-pass imaging of 64-multidetector computed tomography (MDCT) using pharmacological stress has been used to assess myocardial perfusion. However, detection of myocardial ischemia at rest using MDCT has yet to be elucidated. We studied the incidence of myocardial perfusion defect (MPD) by 64-MDCT at rest and the effect of coronary revascularization therapy on MPD in patients with coronary artery disease. HYPOTHESIS: MPD by 64-MDCT at rest indicates myocardial ischemia. METHODS: We studied 76 patients with coronary artery disease who underwent 64-MDCT before and after revascularization therapy and 55 patients who did not undergo revascularization therapy. According to percent diameter stenosis, we defined group A, B, C, and D to have stenosis between 70% and 90%, 50% and 69%, 30% and 49%, and 10% and 29%, respectively. We evaluated regional myocardial contrast enhancement by long and short axis planes. MPD was defined as hypoenhancement area of some extent with CT value <50 HU during diastole. RESULTS: MPD was found in 60.0% and 32.4% of group A and B patients, respectively (P = 0.0176). The incidence was 4.8% and 0% in group C and D patients, respectively (P<0.0001 compared with group A and B). All patients in group A and B and 2 patients with MPD in group C underwent coronary revascularization therapy. MPD disappeared after revascularization therapy in all but 3 group A patients. No patients showed new MPD after revascularization therapy. CONCLUSIONS: Our results demonstrate that a significant percentage of patients with significant coronary artery stenosis show MPD by 64-MDCT at rest, and these MPDs may represent myocardial ischemia.

Relationship between epicardial fat measured by 64-multidetector computed tomography and coronary artery disease.

BACKGROUND: Epicardial fat (EF) is the visceral fat of the heart deposited under the visceral layer of the pericardium and has the same origin as abdominal visceral fat, which is shown to be strongly related to the development of coronary artery disease (CAD). We measured the volume of EF (EFV) by 64-multidetector computed tomography (MDCT) and studied the relationship between EFV and the severity of CAD. HYPOTHESIS: Epicardial fat volume increases steeply in patients with significant coronary artery stenosis and in those with severe coronary artery calcification. METHODS: We studied 197 patients with suspected CAD who underwent 64-MDCT and coronary angiography. Cross-sectional tomographic cardiac slices (3.0 mm thick) from base to apex (30 to 40 slices per heart) were traced semiautomatically and EFV was measured by assigning Hounsfield units ranging from -30 to -250 to fat. RESULTS: Epicardial fat volume was 99.4 ± 40.0 ml (range, 11.6 to 263.8 mL) and coronary artery calcium score (CACS) was 267.2 ± 605.1 (range, 0 to 3780). There was a significant relationship between EFV and CACS (r=0.210, P=0.003). Patients with EFV >100 had a CACS that was significantly higher than in those with EFV <100 (384.0 ± 782.0 vs 174.8 ± 395.6; P = 0.016). The incidence of significant CAD was significantly higher in patients with EFV >100 compared with those with EFV <100 (40.2% vs 22.7%; P=0.008). The EFV was significantly higher in patients with severe coronary artery stenosis and in those with severe coronary artery calcification (CACS >400). CONCLUSIONS: Our results showed that EFV was associated with coronary atherosclerosis, and EFV increased steeply in patients with severe coronary artery stenosis and in those with severe coronary artery calcification.

Prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk by 64-slice computed tomography.

BACKGROUND: Recent research has shown that cardiovascular risk scoring significantly underestimates or misclassifies risk in key subsets of the population. There is a growing need for a noninvasive imaging to detect a subclinical atherosclerosis. Thus we hypothesized that 64-slice computed tomography (CT) could effectively detect subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk. METHODS: Four hundred and fifteen asymptomatic patients with coronary risk factors underwent 64-slice CT. When 64-slice CT showed a significant stenosis we recommended that patients receive stress myocardial perfusion imaging (MPI). When MPI showed ischemic findings, we recommended that patients receive a coronary revascularization procedure. We followed our patients for a mean of 2.8 years (2.4-3.3 years). RESULTS: We detected coronary plaques in 295 patients (71.1%). Of 135 patients with a negative scan for coronary calcification, noncalcified plaques were detected in 15 patients (11.1%). Two hundred and thirty-five patients (79.7%) had multiple plaques and, on average, one patient had 4.6 plaques. Significant coronary stenosis was detected in 91 patients (21.9%) and 85 patients underwent stress MPI. Myocardial ischemia was found in 27 patients (31.8%) and 21 patients underwent percutaneous coronary intervention. For a mean follow-up period of 2.8 years, four patients developed acute coronary syndrome. CONCLUSION: Our results showed that the prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk was very high and one-fifth of them had significant stenosis as shown by 64-slice CT. However, myocardial ischemia was detected in only one-third of them.

Coronary pressure measurement identifies patients with diffuse coronary artery disease who benefit from coronary revascularization.

OBJECTIVE: We analyzed the pressure drop pattern in patients with diffuse coronary artery disease and treated these patients according to their pressure drop pattern. METHODS: We measured pullback coronary pressure from the distal to the proximal left anterior descending coronary artery in 83 patients with diffuse coronary artery disease. Coronary pressure pattern was divided into two types: the abrupt and gradual pressure drop patterns. Patients with an abrupt pressure drop pattern and fractional flow reserve less than 0.75 underwent coronary revascularization. Patients with gradual pressure drop pattern received medical therapy except five patients, who underwent coronary bypass surgery because of triple vessel disease. We followed these patients for 8-20 (14.3±4.6) months using the grading system of the Canadian Cardiovascular Society (CCS grade). RESULTS: Abrupt pressure drop pattern was observed in 47 patients, whereas the remaining 36 patients showed gradual pressure drop pattern. Angiographic findings did not distinguish these pressure drop patterns. All patients with the abrupt pressure drop pattern except one showed symptomatic improvement (the CCS grade decreased from 2.64±0.76 to 1.09±0.35, P<0.01) in response to coronary revascularization. In patients with the gradual pressure drop pattern, 17 of 36 patients showed improvement of symptoms (the CCS grade decreased from 2.31±0.53 to 1.75±0.77, P<0.01). CONCLUSION: Coronary pressure measurement distinguished patients with abrupt pressure drop pattern from those with gradual pressure drop pattern, and the former group of patients benefited from coronary revascularization.

[Clinical experience with intravenous administration of nifekalant hydrochloride for ventricular tachycardia in a hemodialysis patient after open heart surgery].

A 78-year-old man with chronic renal failure (CRF) on hemodialysis (HD) was diagnosed as having severe aortic regurgitation with left ventricular dysfunction. Aortic valve replacement with a 21 mm ATS mechanical bileaflet prosthesis was performed without intraoperative complications. Sustained ventricular tachycardia suddenly occurred 1 day after surgery, then intravenous administration of nifekalant hydrochloride (NIF) was started at a dose of 0.40 mg/kg/hr. Life-threating ventricular arrhythmia was controlled, hemodynamic compromise was improved dramatically. NIF was regulated with a low-dose of 0.24 mg/kg/hr to prevent malignant side effect such as torsa de pointes. Since QTc was elongated to 0.57 seconds 11 hours after administration, NIF was stopped. Low-dose intravenous administration of NIF in patients with CRF on HD could be useful to prevent ventricular tachyarrhythmias without any adverse effect after cardiac surgery.

Prevalence of non-calcified coronary plaque on 64-slice computed tomography in asymptomatic patients with zero and low coronary artery calcium.

OBJECTIVES: To study the prevalence of noncalcified plaque in asymptomatic low-risk patients with no or mild coronary artery calcium (CAC). METHODS: From 502 patients with coronary risk factors who underwent 64-slice computed tomography, 224 asymptomatic patients were identified with no CAC (n=117) or mild CAC (n=107; defined as patients with Agatston scores from 1 to 100). RESULTS: Patients with no CAC were younger and had diabetes less often. Medications and laboratory data were not significantly different between the two groups. The prevalence of noncalcified plaque was 11.1% in patients with no CAC and 23.4% in the mild CAC group (P=0.0142). Multiple plaques were detected in 2.6% of the group with no CAC and 3.7% of the group with mild CAC (P=0.5934). Significant coronary artery stenosis was found in one patient in the group with no CAC (0.9%) and three patients in the group with mild CAC (2.8%, P=0.3506). CONCLUSIONS: Significant percentages of noncalcified plaque were found in asymptomatic low-risk patients with no or mild coronary calcium.

Distribution of coronary atherosclerosis in patients with coronary artery disease.

The distribution of coronary atherosclerosis has not been fully clarified. We measured coronary artery calcium score (CACS) in 624 consecutive patients for the right coronary artery (RCA), left main trunk (LMT), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCx), then calculated total CACS. Coronary artery calcium score was measured using the Agatston method. We divided these patients into four groups: CACS 1-100 (Group A, n = 267), CACS 101-400 (Group B, n = 160), CACS 401-1000 (Group C, n = 110), and CACS >1000 (Group D, n = 87). In Group A, B, and C, the CACS in LAD was significantly higher than in the other three arteries (P < 0.0001). In Group D, the CACS was not significantly different between LAD and RCA (P = 0.6930). In Groups A, B, and C, coronary artery calcium (CAC) was more frequently found in LAD compared with other arteries (P < 0.0001). However, in Group D the prevalence of CAC was not significantly different among the three arteries (P = 0.4435). Coronary artery calcium was found more frequently in LAD than in the other coronary arteries in patients with mild to high CAC, but not in those with very high CAC.

Prevention of coronary slow flow/no reflow during percutaneous coronary intervention by the use of embolic protection device, 'Filtrap'.

A 68 year-old man underwent percutaneous coronary intervention (PCI). A 64 multi-slice computed tomography (MSCT) demonstrated a non-calcified plaque with positive remodeling. Intravascular ultrasound showed severe attenuation which suggested high risk of coronary no reflow during PCI. In order to avoid this, we used an embolic protection device, Filtrap. Immediately after deployment of a Taxus stent, ST-elevation with chest pain and coronary no reflow appeared. After retrieval of the Filtrap device, ST-elevation and no reflow disappeared. The filter was filled with yellow materials. This case suggests two things: that 64 MSCT can detect coronary plaque with high-risk of coronary no reflow during PCI; and that using a Filtrap device can effectively prevent the coronary no reflow during PCI.

Coronary pressure measurement based decision making for percutaneous coronary intervention.

The fractional flow reserve (FFR) is a simple, reliable, and reproducible physiologic index of lesion severity. In patients with intermediate stenosis, FFR≥0.75 can be used to safely defer percutaneous coronary intervention (PCI), and patients with FFR≥0.75 have a very low cardiac event rate. Coronary pressure measurement can determine which lesion should be treated with PCI in patients with tandem lesions, and PCI on the basis of FFR has been demonstrated to result in an acceptably low repeat PCI rate. FFR can identify patients with equivocal left main coronary artery disease who benefit from coronary bypass surgery. Coronary pressure measurement distinguishes patients with an abrupt pressure drop pattern from those with a gradual pressure drop pattern, and the former group of patients benefit from PCI. Coronary pressure measurement is clinically useful in evaluating sufficient recruitable coronary collateral blood flow for prevention of ischemia, which affects future cardiac events. FFR is useful for the prediction of restenosis after PCI. As an end-point of PCI, FFR ≥0.95 and ≥0.90 would be appropriate for coronary stenting and coronary angioplasty, respectively. In summary, if you encounter a coronary stenosis in doubt you should measure pressure rather than dilate it.

Prevalence of subclinical atherosclerosis in asymptomatic diabetic patients by 64-slice computed tomography.

OBJECTIVES: Patients with diabetes have a 2-fold to 4-fold higher risk of a cardiovascular event than nondiabetic patients. Thus there is a need to identify patients with diabetes who are at risk of cardiovascular events before the onset of symptoms. We studied the prevalence of coronary artery disease in asymptomatic diabetic patients compared with asymptomatic nondiabetic patients by 64-slice computed tomography (CT). METHODS: From 425 asymptomatic patients with coronary risk factors but without known coronary artery disease who underwent 64-slice CT, we identified 93 asymptomatic diabetic patients (diabetic group) and 93 age-matched and sex-matched asymptomatic nondiabetic patients. RESULTS: Clinical characteristics were not significantly different between the two groups. Total coronary calcium score was significantly higher in diabetic group than that in nondiabetic group (median 117 vs. 53.5, P<0.0001). No coronary calcium was detected in 30.0% of nondiabetic group compared with 15.1% of diabetic group (P=0.0022). Coronary calcium score more than 400 was detected in 9.7% of nondiabetic group compared with 36.6% of diabetic group (P<0.0001). Coronary plaques were found in 67.7% of nondiabetic group compared with 91.4% of diabetic group (P<0.0001). Multiple plaques were detected in 57.0 and 77.4% of patients in nondiabetic and diabetic group, respectively (P=0.0030). Significant coronary stenosis was found in 16.1% of nondiabetic group compared with 33.3% of diabetic group (P=0.0065). CONCLUSION: Our results show that the prevalence of coronary plaques detectable by 64-slice CT in asymptomatic diabetic patients is very high.

Comparison of the effects of nicorandil versus verapamil on the incidence of slow flow/no reflow during rotational atherectomy.

In rotational atherectomy, the slow-flow/no-reflow phenomenon is a common complication, which usually results in myocardial injury. We prospectively randomized 111 patients with successful rotational atherectomy into a verapamil group (group V, n = 56) and a nicorandil group (group N, n = 55). We compared final burr size, total ablation time, maximum decrease in revolutions per minute, incidence of slow flow/no reflow, creatine kinase-MB increase, and cardiac troponin T increase between the 2 groups. Patient and procedural characteristics were not significantly different between groups. The incidence of no reflow/slow flow was significantly lower in group N than in group V (3.6% vs 17.9%, respectively, p <0.05). The incidence of a minor increase in cardiac markers was also significantly lower in group N than in group V (creatine kinase-MB 3.6% vs 16.1%, p <0.05; cardiac troponin T 5.5% vs 21.4%, p <0.05). In conclusion, our results showed that nicorandil decreases the incidence of slow flow/no reflow during rotational atherectomy.