Jae-Youn Moon

Quantification of regional calcium burden in chronic total occlusion by 64-slice multi-detector computed tomography and procedural outcomes of percutaneous coronary intervention

BACKGROUND One of the most important reasons for failure of percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) is calcified plaque, which either prevents passage of guide wire or ruptures after balloon inflation. We sought to evaluate whether quantified calcium contents of CTO on multi-detector computed tomography (MDCT) correlate with immediate procedural outcomes. METHODS Sixty-four patients with 72 CTO lesions who underwent 64-slice MDCT prior to PCI were investigated. The lesions were divided into 2 groups according to procedural outcomes (55 lesions with PCI-success group, 17 lesions with PCI-failure group). Clinical, angiographic and MDCT parameters, including regional calcium volume (RCaV), regional calcium score (RCaS), regional calcium equivalent mass (RCaEq), and relative calcium area at the most calcified cross section of CTO (%CaS/CSA), were compared between the two groups. RESULTS The duration of CTO was shorter in PCI-success group than PCI-failure group (7.16 ± 10.5 vs 15.59 ± 14.92 months, p=0.011), and the procedural success rate was 76.3%. Regional calcium-related parameters (RCaV 52.86 ± 58.39 vs 7.26 ± 15.27 mm(3), p<0.001; RCaS 72.71 ± 78.4 vs 9.66 ± 20.2, p<0.001; RCaEq 12.58 ± 12.97 vs 1.84 ± 3.716 mgCaHA, p<0.001; %CaS/CSA 53.9 ± 20.3 vs 30.4 ± 17.1%, p=0.009) in the occluded segment were higher and the occlusion length was longer (37.44 ± 27.48 vs 22.00 ± 18.04 mm, p<0.021) in PCI-failure group compared to PCI-success group. Multivariate regression analysis showed that only %CaS/CSA was a significant determinant of PCI-failure. CONCLUSIONS Precise quantification of regional calcification and measurement of the occluded segment by high resolution MDCT can deliver important information for predicting procedural outcomes in PCI of CTO.

Lipoprotein(a) and LDL Particle Size Are Related to the Severity of Coronary Artery Disease

Background: The pathophysiological role and metabolic pathway of Lp(a) have not been clearly defined. An association between Lp(a) and oxidative low-density lipoprotein (LDL) were recently reported. And small dense LDL (sd-LDL) were associated with circulating malondialdehyde-modified LDL. We investigated the relationships between serum Lp(a) level and LDL particle size in coronary artery disease (CAD) patients. Further, we investigated the relationships of sd-LDL and Lp(a) with the extent and severity of CAD. Methods: A total of 490 patients (mean: 60.5 ± 11.5 years old) who underwent coronary angiography to evaluate chest pain were investigated. Patients were classified into two groups, a CAD group (n = 256), who had significant stenosis observed by coronary angiogram, and a control group (n = 234), who had normal, or minimal coronary arteries. CAD severity was measured by Gensini scores. The distribution of the LDL subfraction was analyzed using a Quantimetrix Lipoprint LDL System. Results: The serum Lp(a) concentration was correlated with the fraction of sd-LDL (r = 0.193, p < 0.001) and mean LDL size (r = 0.160, p = 0.003). The Lp(a) level and mean LDL particle size were significantly correlated with a high Gensini score. LDL particle size in the CAD group was smaller than in the control group (26.74 ± 0.64 vs. 26.43 ± 0.93 nm, p < 0.001). The Gensini score was significantly higher in small LDL with high Lp(a) level groups. Conclusion: The positive correlation of the level of Lp(a) and sd-LDL fraction were demonstrated. The mechanism of this association is not clearly defined; we can suggest that it may stem from the individual atherogenic condition that linked to increased oxidative stress. Both increased Lp(a) and sd-LDL fraction were correlated with the severity of CAD.

The Utility of Multi-detector Row Spiral CT for Detection of Coronary Artery Stenoses

Contrast-enhanced multi-detector row spiral computed tomography (MDCT) was introduced as a promising noninvasive method for vascular imaging. This study examined the accuracy of this technique for detecting significant coronary artery stenoses. Both MDCT(Sensation 16, Siemens, Germany, 12 × 0.75 mm collimation and 0.42 sec rotation speed, 120 kV, 500 effective mA, and 2.7 mm/rotation table-feed) and invasive coronary angiography (CAG) were performed on 61 patients (mean age 59.2 ± 10, 44 men) who were suspected of having coronary artery disease. All patients were treated with atenolol (25 - 50 mg) prior to imaging and the heart rate was maintained below 65 beats per minutes during image acquisition. The images were reconstructed in the diastole around TI - 400 ms with a 0.5 mm increment and a 1.0 mm thickness. All coronary arteries with a diameter of 2.0 mm or more were assessed for the presence of a stenosis (> 50% luminal narrowing). Two independent radiologists who were unaware of the results of the invasive CAG evaluated the MDCT data, and the results were compared with those from the invasive CAG (interval 1- 27, mean 11 days). An evaluation of the CT coronary angiogram (CTCA) was possible in 58 of the 61 patients (95%). Image acquisition of the major coronary arteries including the left main trunk was available in 229 out of 244 arteries. Invasive CAG showed that 35 out of 58 patients had significant coronary artery stenoses by. patient analysis of those who could be evaluated showed that CT coronary angiography correctly classified 30 out of 35 patients as having at least 1 coronary stenosis (sensitivity 85.7%, specificity 91.3%, positive predictive value 93.8%, negative predictive value 80.8%). By analyzing each coronary artery, CAG found 62 stenotic coronary arteries in the 229 coronary arteries that could be evaluated. MDCT correctly detected 50 out of 62 stenotic coronary arteries and an absence of stenosis was correctly identified in 156 out of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%, positive predictive value 81.9%, negative predictive value 92.8%). The non-invasive technique of MDCT for examining the coronary artery appears to be a useful method for detecting coronary artery stenoses with a high accuracy particularly with the proximal portion and large arteries.

Noncompaction of the ventricular myocardium combined with polycystic kidney disease

Noncompaction of the ventricular myocardium (NVM) is a rare cardiac abnormality of unknown etiology. The condition is characterized by prominent and excessive trabeculations in a ventricular wall segment, with deep intertrabecular spaces perfused from the ventricular cavity. Polycystic kidney diseases are characterized by the formation of multiple cysts in the kidneys and liver and, less frequently, in the pancreas. Cardiovascular abnormalities including hypertension, mitral valve prolapse, and intracranial aneurysms are also frequently recognized. However, polycystic kidney disease and isolated ventricular noncompaction have not previously been correlated. Here, we describe one case of isolated noncompaction of ventricular myocardium with polycystic kidney disease, coupled with a progressive worsening of heart failure. We confirmed these abnormalities using contrast echocardiography, abdominopelvic computed tomography, and cardiac magnetic resonance imaging.

Impact of coronary artery collaterals on infarct size assessed by serial cardiac magnetic resonance imaging after primary percutaneous coronary intervention in patients with acute myocardial infarction.

ObjectivesCoronary collaterals have been shown to protect ischemic myocardium from necrosis in patients with acute myocardial infarction (AMI). We sought to determine the impact of collateral circulation on infarct size in AMI using serial cardiac magnetic resonance (CMR). MethodsA total of 46 anterior AMI patients (age, 58.9±10.6 years; male 72.3%) undergoing primary percutaneous coronary intervention (PCI) were investigated. The infarct size was measured on serial CMR performed within 7 days after primary PCI (acute stage) and 3 months later (chronic stage). ResultsThirty-four patients (73.9%) showed collateral flow before primary PCI. CMR taken at the acute stage showed no significant difference in infarct size between two groups. However, follow-up CMR revealed significantly smaller percentage of infarct thickness (51.8±14.0 vs. 62.5±11.7%, P = 0.035) and mass (22.3±9.9 vs. 30.9±11.6%, P = 0.042) in patients with collaterals. There were significant changes from the acute to chronic stage regarding left ventricular end-systolic (−18.2±10.0 vs. 0.8±2.5 ml, P = 0.022) and end-diastolic volume (−14.8±9.2 vs. 2.6±13.7 ml, P = 0.031), percentage of infarct mass (−6.1±2.8 vs. −0.8±1.1%, P = 0.034), and thickness (−8.9±3.3 vs. −3.1±2.8%, P = 0.029) in collateral group compared with noncollateral group on serial CMR. ConclusionSerial CMR revealed the effect of collaterals in patients with AMI on reduction of infarct size and improvement of myocardial remodeling at the chronic stage.

Intravascular Ultrasound Evaluation of Optimal Drug-Eluting Stent Expansion After Poststent Balloon Dilation Using a Noncompliant Balloon Versus a Semicompliant Balloon (from the Poststent Optimal Stent Expansion Trial (POET))

The impact of type of balloon such as noncompliant (NC; Quantum) or semicompliant (SC; Maverick(2)) used after stent dilation on optimal stent expansion (OSE) has not been established for drug-eluting stents (DESs). We conducted a prospective multicenter, randomized study to compare NC with SC balloons after stent balloon dilatation. A total of 301 patients (127 men, 83 women, 62 +/- 9 years of age) treated with a DES (sirolimus-eluting stent [SES], n = 152; paclitaxel-eluting stent, n = 149) were included. OSE followed the definition of the Multicenter Ultrasound Stenting in Coronaries (MUSIC) study. The primary end point was the incidence of OSE using intravascular ultrasound according to type of balloon. Baseline characteristics of each group showed no significant differences. OSE in the SC balloon group was achieved at higher rates than the NC balloon group (53 +/- 35%, vs 73 +/- 48%, p = 0.022 in all stents; 25 +/- 33%, vs 36, 48%, p = 0.051 in SESs). However, any differences in the achievement of OSE between the NC and SC balloon groups were not present in paclitaxel-eluting stents. In conclusion, despite postadjuvant balloon inflations with high pressures, underexpansion of the DES was seen commonly. Between the 2 types of balloon for adjuvant dilation after DES implantation, same-size SC balloons could be more useful for obtaining OSE than NC balloons, especially in SESs.

Preventive effect of pretreatment with intravenous nicorandil on contrast-induced nephropathy in patients with renal dysfunction undergoing coronary angiography (PRINCIPLE Study).

Purpose To investigate the effect of pretreatment with intravenous nicorandil on the incidence of contrast-induced nephropathy (CIN) in patients with renal dysfunction undergoing coronary angiography. Materials and Methods This randomized controlled multicenter study enrolled a total of 166 patients (nicorandil n=81; control n=85) with an estimated glomerular filtration rate <60 mL/min. Nicorandil 12 mg dissolved in 100 mL of 0.9% saline was administered intravenously for 30 minutes just prior to coronary angiography in the nicorandil group. The same volume of only saline was given to the control group. The primary end-point was the incidence of CIN, defined as >0.5 mg/dL increase or >25% rise in serum creatinine (SCr) concentration within 48 hours of contrast exposure compared to baseline. Results The final analysis included 149 patients (nicorandil n=73; control n=76). The baseline characteristics and the total volume of the used contrast (Iodixanol, 125.6±69.1 mL vs. 126.9±74.6 mL, p=0.916) were similar between the two groups. The incidence of CIN also did not differ between the nicorandil and control groups (6.8% vs. 6.6%, p=0.794). There was no difference between the two groups in the relative change in SCr from baseline to peak level within 48 hours after coronary angiography (-1.58±24.07% vs. 0.96±17.49%, p=0.464), although the nicorandil group showed less absolute change in SCr than the control group (-0.01±0.43 mg/mL vs. 0.02±0.31 mg/mL, p=0.005). Conclusion Prophylactic intravenous infusion of nicorandil did not decrease the incidence of CIN in patients with renal dysfunction undergoing coronary angiography.

Association of insulin resistance and coronary artery remodeling: an intravascular ultrasound study

BackgroundThere are few studies that investigated the correlation between insulin resistance (IR) and the coronary artery remodeling. The aim of the study is to investigate the association of IR measured by homeostasis model assessment of insulin resistance (HOMA-IR) and coronary artery remodeling evaluated by intravascular ultrasound (IVUS).MethodsA total of 298 consecutive patients who received percutaneous coronary interventions under IVUS guidance were retrospectively enrolled. The value of HOMA-IR more than 2.5 was considered as IR positive. Metabolic syndrome was classified according to NCEP ATP III guidelines. The remodeling index was defined as the ratio of the external elastic membrane (EEM) area at the lesion site to the EEM area at the proximal reference site.ResultsA total of 369 lesions were analyzed (161 lesions in HOMA-IR positive and 208 lesions in HOMA-IR negative). Remodeling index was significantly higher in the HOMA-IR positive group compared with the negative group (HOMA-IR positive vs. negative: 1.074 ± 0.109 vs. 1.042 ± 0.131, p = 0.013). There was a significant positive correlation between remodeling index and HOMA-IR (p = 0.010). Analysis of HOMA-IR according to remodeling groups showed increasing tendency of HOMA-IR, and it was statistically significant (p = 0.045). Multivariate analysis revealed that only HOMA-IR was an independent predictor of remodeling index (r = 0.166, p = 0.018).ConclusionIncreased IR estimated by HOMA-IR was significantly associated with a higher remodeling index and positive coronary artery remodeling.

Increase of metabolic syndrome score is an independent determinant of increasing pulse pressure.

Purpose The objective of this study was to determine whether the progressive increase of metabolic syndrome (MetS) score, the number of components of MetS, is correlated significantly with increasing pulse pressure (PP). Materials and Methods 4,034 subjects were enrolled from the Cardiovascular Genome Center of Yonsei University (M : F = 2344 : 1690, 55.2 ± 10.5). Most of the study population were recruited from hypertension clinics, controlled with medications according to JNC7 guidelines. The Asian modified criteria of MetS were applied and MetS score was estimated. The HOMA index for insulin resistance, cholesterol profiles, and anthropometric measurements were assessed. Results Among 4034 participants, 1690 (41.9%) were classified as MetS. Progressive increase in PP was demonstrated for increasing components of the MetS score. Multiple linear regression analysis with PP as the dependent variable showed that age (β = 0.311, p < 0.001), MetS score (β = 0.226, p < 0.001), male gender (β = -0.093, p < 0.001) and HOMA index IR (β = 0.033, p = 0.03) are significantly associated with PP (R2 = 0.207, p < 0.001). Conclusion The present results from this study demonstrate that increasing MetS score is an independent determinant of increasing PP. The results also demonstrate the independent role of MetS in increasing arterial stiffness and PP.

An exaggerated blood pressure response to exercise is associated with subclinical myocardial dysfunction in normotensive individuals.

Objectives: An exaggerated blood pressure (BP) response to exercise is associated with adverse cardiovascular outcomes, even in normotensive individuals. The purpose of this study was to compare myocardial function between normotensive individuals with and without an exaggerated BP response. Methods: We evaluated global myocardial function using speckle tracking echocardiography in normotensive individuals. Two-dimensional speckle tracking echocardiography and a treadmill exercise test were performed simultaneously in 171 normotensive individuals (mean age: 48 ± 8 years; 97 men) without any structural heart disease. Results: Among 171 normotensive individuals, 19 (11%) exhibited an exaggerated BP response (≥200 mmHg for men and ≥190 mmHg for women) during the treadmill test. Conventional echocardiographic parameters were similar between the two groups. However, on strain analyses, the systolic and early diastolic global longitudinal strains of the left ventricle (LV) and left atrium were lower in individuals with an exaggerated BP response to exercise. The peak SBP during exercise was inversely related to systolic global longitudinal strain of the LV (r = –0.35, P < 0.01) and left atrium (r = –0.41, P < 0.01). On multivariate analyses, an exaggerated BP response to exercise was shown to be an independent determinant of reduced global longitudinal strain of the LV (&bgr; = –0.20, P < 0.05) and left atrium (&bgr; = –0.28, P < 0.05). Conclusion: Normotensive individuals with an exaggerated BP response to exercise exhibit impairment in longitudinal myocardial function. Even without apparent hypertension, an exaggerated BP response could cause repeated increases in afterload and result in subclinical myocardial dysfunction.