Spot drug-eluting stenting for long coronary stenoses: long-term results of a randomized clinical study.

BACKGROUND: Preliminary results of a randomized trial have suggested that total lesion coverage with drug-eluting stents (DES) is not necessary in the presence of diffuse disease of nonuniform severity. In the present study, we report long-term results of this trial. METHODS: Consecutive, consenting patients with a long (>20 mm) coronary lesion of nonuniform severity and indication for percutaneous coronary intervention were randomized to full stent coverage of the atherosclerotic lesion with multiple, overlapping (full DES group, n = 90) or spot stenting of the hemodynamically significant parts of the lesion only (defined as diameter stenosis > 50%) (spot DES group, n = 89). RESULTS: At a follow-up of 2-7 years, 30 patients with full DES (33.3%) and 12 patients (13.5%) with spot DES had a major adverse cardiac event (MACE) (P = 0.015). Cox proportional hazard model showed that the risk for MACE was almost 65% lower among patients who were subjected to spot DES compared to those who underwent full DES (HR = 0.35, 95% CI = 0.18-0.68, P = 0.002). This association remained significant even after controlling for age, sex, and lesion length, and the type of stent used (HR = 0.41, 95% CI = 0.20-0.81, P = 0.011). CONCLUSIONS: In the presence of diffuse disease of nonuniform severity, selective stenting of only the significantly stenosed parts of the lesion confers better long-term results compared to total lesion coverage with DES.

Three-dimensional analysis of the left anterior descending coronary artery: comparison with conventional coronary angiograms.

OBJECTIVE: This study aimed at comparing three-dimensional (3-D) reconstruction with two-dimensional coronary angiograms with respect to anatomical parameters that might affect plaque formation and rupture. METHODS: Sixty patients with stable left anterior descending (LAD) lesions and 60 patients with an anteroseptal myocardial infarction and recanalized LAD were studied. RESULTS: Conventional angiography significantly underestimated the distance of the stenosis from the ostium of the LAD, 29.4+/-14.5 versus 35.3+/-18.5 mm, P<0.001. Vessel curvature at the site of the lesion was overestimated by conventional angiography compared with 3-D reconstruction, 147.6+/-30.6 degrees versus 162.3+/-11.2 degrees , P<0.001, as was axial bending of the LAD owing to ventricular contraction (17.8+/-7.78 degrees vs. 8.9+/-8.9 degrees , P<0.001). No agreement was observed between two-dimensional and 3-D analysis for either curvature on lesion or axial bending assessment, with intraclass correlation coefficient values 0.155 (-0.009, 0.315) and -0.022 (-0.183, 0.174), respectively. No significant agreement was found between the two methods in the detection of on-stenosis bifurcations (1.7%, kappa=0.086, P=0.349). CONCLUSION: Conventional coronary angiography cannot provide accurate estimates of anatomical parameters, such as distance of a coronary stenosis from the ostium of the vessel, coronary artery curvature at the site of stenosis, axial deformity and bending because of ventricular contraction, and classification of bifurcations. Reconstruction of the coronary tree in 3-D space is necessary for such estimations.

Handgrip-enhanced myocardial fractional flow reserve for assessment of coronary artery stenoses.

BACKGROUND: Fractional flow reserve (FFR) may yield false-negative results in up to 12% of lesions tested, and there is a zone of uncertainty at borderline values. METHODS: Forty-eight patients were investigated by means of dobutamine stress echocardiography (DSE), coronary angiography, and FFR assessment of 48 coronary lesions before, during, and immediately after handgrip exercise. RESULTS: Mean FFR values were lower during and immediately after handgrip exercise as compared with baseline (0.86 +/- 0.09 vs 0.87 +/- 0.08 vs 0.88 +/- 0.08, P < .05, respectively). The sensitivity of FFR < or = 0.75 for predicting myocardial ischemia on DSE was 17.6% before handgrip exercise, 52.9% during, and 35.5% immediately after exercise. The specificity of FFR < or = 0.75 before, during, and immediate after exercise was 100%, 93.5%, and 96.8%, respectively. In 10 patients, FFR values > 0.75 before handgrip became < or = 0.75 during or immediately after handgrip exercise (P = .01). All these patients had angina and/or DSE indicating ischemia in the territory of the vessel studied, and underwent coronary intervention. At 6 months follow-up, all patients were asymptomatic with negative DSE tests. CONCLUSIONS: The addition of handgrip exercise can significantly lower the FFR and potentially improve its ability to detect physiologically significant stenoses.

Effect of slow pathway ablation in atrioventricular nodal reentrant tachycardia on the electrophysiologic characteristics of the inferior atrial inputs to the human atrioventricular node.

The inferior atrial extensions of the atrioventricular (AV) node have been related to the anatomic substrate of the slow pathway, but their role in AV nodal reentrant tachycardia (AVNRT) is unknown. Ten patients with slow-fast AVNRT were studied before and after successful slow pathway ablation. Simultaneous His bundle recordings from the right and left sides of the septum were made during right and left inferoparaseptal pacing. Longer stimulus to His (St-H) intervals were measured during right inferoparaseptal pacing than during left inferoparaseptal pacing (284 +/- 55 vs 246 +/- 46 ms, p = 0.005 for right His recordings and 283 +/- 56 vs 244 +/- 46 ms, p = 0.005 for left His recordings) at similar coupling intervals during AVNRT induction. After ablation, the St-H intervals at the maximum AV nodal conduction decrement were similar during right inferoparaseptal and left inferoparaseptal pacing (217 +/- 32 vs 207 +/- 21 ms, p = 0.10 for right His and 215 +/- 32 vs 206 +/- 20 ms, p = 0.13 for left His) at similar coupling intervals. The difference (DeltaSt-H) between St-H intervals during AVRNT induction or at the maximum conduction decrement and during constant pacing for right His recordings with right inferoparaseptal pacing were significantly greater than DeltaSt-H measured with left His during left inferoparaseptal pacing (173 +/- 64 vs 137 +/- 55 ms, p = 0.005) before ablation, but not after (117 +/- 39 vs 100 +/- 40 ms, p = 0.44). Resetting of AVNRT with delivery of left inferoparaseptal extrastimuli was achieved in 7 of 10 patients. In conclusion, the electrophysiologic characteristics of the right and left inferior atrial inputs to the human AV node in patients with AVNRT and their response to slow pathway ablation provide further evidence that the inferior nodal extensions represent the anatomic substrate of the slow pathway.

Latent arterial hypertension in apparently lone atrial fibrillation.

INTRODUCTION: Longitudinal studies on lone AF are rare and the incidence of hypertension in this population unknown. This study aimed at investigating the incidence of arterial hypertension in patients with apparently lone atrial fibrillation (AF). METHODS AND RESULTS: Out of 292 consecutive patients presented with permanent or paroxysmal AF, 32 patients were diagnosed as having lone AF according to strict criteria. Three patients were subjected to ablation of the ligament of Marshall, 14 patients to pulmonary vein isolation, and the remainder were treated with beta blockade. Patients were followed-up for a 1-3 year period. During follow-up, 14 patients were diagnosed as having arterial hypertension. Thirteen of them had recurrent AF despite ligament of Marshall ablation (1 patient), pulmonary vein isolation (4 patients) and beta blockade (8 patients). Cox regression analysis revealed that the only significant predictor of development of hypertension was complete or partial response to antiarrhythmic therapy (beta=3.82, S.E.=1.22, exp(b)=45.63, 95% C.I.=4.17-499.2, p=0.001), independent of age (beta=-0.01, p=0.74), sex (beta=-0.91, p=0.28), left ventricular ejection fraction (beta=0.06, p=0.52), left atrial size (beta=0.58, p=0.7) and kind of antiarrhythmic therapy (ablation or drug therapy) (beta=1.36, p=0.09). In patients with lone AF that did not respond at all to antiarrhythmic therapy, there was a 45.6 times higher risk of diagnosing hypertension during the next 3 years as compared to responders. CONCLUSION: Approximately 44% of patients with an initial diagnosis of lone AF may represent occult cases of arterial hypertension. In these patients hypertension may affect AF recurrence and treatment outcomes, regardless of the mode of antiarrhythmic therapy used.

Patient dosimetry during coronary interventions: a comprehensive analysis.

BACKGROUND: We performed a detailed analysis of patient radiation during coronary interventions, comparing dose measurements to established dose reference levels, assessing coronary artery doses, and estimating total radiation risk of fatal cancer. METHODS: We prospectively examined 281 patients who were subjected to 307 percutaneous coronary interventions. RESULTS: The mean kerma area product (KAP) per procedure was 82.1 +/- 47.9 Gy x cm2. Corresponding values for fluoroscopy and digital cineangiography were 28.3 +/- 25.5 Gy x cm2 and 53.8 +/- 35.5 Gy x cm2, respectively, and exposure times were 13.1 +/- 6.8 minutes (87%) and 2.0 +/- 1.5 minutes (13%), respectively. The right anterior oblique caudal and left anterior oblique cranial projections accounted for the highest amount of KAP (24.0% and 23.1%, respectively) compared with other projections. The maximum recorded skin-dose was 182 mGy. Performing a representative procedure on a phantom, the effective dose was 14.9 mSv. The mean coronary dose was 61.7 +/- 38.2 mGy, with a highest calculated dose of 220.1 mGy. The third quartile of KAP measurements was 105 Gy x cm2, the 95th percentile was 175 Gy x cm2, and the mean value of KAP measurements was 82 Gy x cm2. The total risk for the development of fatal cancer was calculated as 83 cases for every 100,000 patients subjected to coronary intervention. CONCLUSIONS: A detailed analysis of patient radiation during coronary interventions is presented. Coronary doses and total radiation risk of fatal cancer are also calculated, and a method for establishing dose reference level values is proposed.

Comparison of effectiveness of carvedilol versus bisoprolol for maintenance of sinus rhythm after cardioversion of persistent atrial fibrillation.

Ninety patients who underwent cardioversion of persistent atrial fibrillation (AF) were randomized to bisoprolol 5 to 10 mg once daily or carvedilol 12.5 to 25 mg twice daily. Using intention-to-treat analysis, 23 patients (46%) in the bisoprolol group and 17 patients (32%) in the carvedilol group relapsed into AF during the 1 year of total follow-up (p = 0.486). Patients treated with carvedilol had a 14% (hazard ratio 0.86) lower risk of relapse of AF compared with patients in the bisoprolol group, although results were statistically insignificant (p = 0.661) after controlling for patient age, gender, baseline heart rate, and left atrial diameter.

Right and left inferior extensions of the atrioventricular node may represent the anatomic substrate of the slow pathway in humans.

OBJECTIVES: The purpose of this study was to investigate the electrophysiologic characteristics of the inferior extensions of the human atrioventricular (AV) node and their possible relationship to slow pathway conduction. BACKGROUND: The human heart contains right and left inferior extensions of the AV node that relate to right and left atrial inputs. METHODS: Fourteen patients admitted for catheter ablation of left-sided accessory pathways were studied. Atrial pacing was performed from multiple sites in both atria, and simultaneous His-bundle recordings from right and left sides of the septum were made. RESULTS: Significant differences of A-H and stimulus to His (St-H) intervals with pacing at various sites were found. St-H intervals were similar during constant pacing from the low right atrium or the left inferoparaseptal area (112 +/- 28 ms vs 112 +/- 26 ms, P = .8, for right His recordings and 114 +/- 23 ms vs 111 +/- 25 ms, P = .9, for left His recordings). At maximum decrement, there were significantly shorter St-H intervals during left inferoparaseptal pacing compared to low right atrial pacing (201 +/- 24 ms vs 218 +/- 44 ms, P = .02, for right His recordings, and 200 +/- 24 ms vs 219 +/- 41 ms, P = .009, for left His recordings). Differences on right His recordings between St-H intervals at maximum decrement and at constant pacing from the low right atrium were significantly higher than corresponding differences on left His recordings during pacing from the left inferoparaseptal area (P = .035). CONCLUSIONS: Our findings support the concept that the right and left inferior extensions of the human AV node may represent the anatomic substrate of the slow pathway as defined electrophysiologically.

Medical personnel and patient dosimetry during coronary angiography and intervention.

Percutaneous coronary interventions are associated with increased radiation exposure compared to most radiological examinations. This prospective study aimed at (1) measuring entrance doses for all in-room personnel, (2) performing an assessment of patient effective dose and intracoronary doses, (3) investigating the contribution of each projection to kerma-area product (KAP) and irradiation time, (4) comparing results with established DRL values in this clinical setting and (5) estimating the risk for fatal cancer to patients and operators. Measurements were performed during 40 consecutive procedures of coronary angiography (CA), half of which were followed by ad hoc coronary angioplasty (PTCA). KAP measurements were used for patients and thermoluminescent dosimetry for the in-room personnel. The mean KAP value per procedure for CA was 29 +/- 9 Gy cm2. Thirty four per cent of KAP was due to fluoroscopy, whereas the remainder (66%) was due to digital cine. Accordingly, the mean KAP value per PTCA procedure was 75 +/- 30 Gy cm2, and contribution of fluoroscopy is 57%. Effective dose per year was estimated to be 0.04-0.05 mSv y(-1) for the primary operator, and 0.03-0.04 mSv y(-1) for those assisting. Corresponding measurements for radiographer and nurse were below detectable level, implying minimal radiation hazards for them. Regarding radiation exposure, coronary intervention is considered a quite safe procedure for both patients and personnel in laboratories with modern equipment and experienced operators as long as standard safety precautions are considered. Exposure optimization though should be constantly sought through continuous review of procedures.

Plasma profiles of peripheral monocyte-related inflammatory markers in patients with arterial hypertension. Correlations with plasma endothelin-1.

BACKGROUND: This study investigates the plasma activity of inflammatory mediators such as granulocyte-macrophage colony-stimulating factor (GM-CSF), C-C chemokines and soluble adhesion molecules, produced by monocyte-endothelial cell adhesive interaction, in patients with arterial hypertension. METHODS: We studied 66 untreated patients with mild to moderate arterial hypertension (hypercholesterolemic: 34, normocholesterolemic: 32) and 30 sex- and age-matched normocholesterolemic normotensive controls. Plasma concentrations of GM-CSF, macrophage chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha), RANTES (regulated on activation normally T-cell expressed and secreted), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1), as well as plasma endothelin-1 (ET-1), were determined in study population by ELISA and RIA, respectively. RESULTS: Hypertensives exhibited significantly higher levels of GM-CSF (6.5+/-1.3 vs. 2.3+/-0.7 pg/ml, P=0.099), MCP-1 (175+/-31 vs. 120+/-24 pg/ml, P=0.0093), MIP-1alpha (23+/-4 vs. 15+/-2 pg/ml, P=0.0089), RANTES (17+/-4 vs. 14+/-3 ng/ml, P=0.047), sICAM-1 (235+/-39 vs. 187+/-21 ng/ml, P=0.0041), sVCAM-1 (684+/-42 vs. 589+/-23 ng/ml, P=0.0045) and ET-1 (6.1+/-1.5 vs. 2.4+/-0.3 pg/ml, P=0.0095) than those of normotensives. The normocholesterolemic hypertensives had significantly lower levels of GM-CSF, MCP-1, MIP-1alpha, sICAM-1 and sVCAM-1 than hypercholesterolemic hypertensives but higher than normotensives. In hypertensives, ET-1 levels were significantly correlated with mean arterial pressure (r=0.51, P=0.028), MCP-1 values (r=0.45, P=0.047) and sICAM-1 levels (r=0.64, P=0.0090). Significant correlations were also found between LDL cholesterol values and plasma inflammatory factors GM-CSF (r=0.58, P=0.0088), MCP-1 (r=0.49, P=0.040) and sICAM-1 (r=0.53, P=0.034) in the hypercholesterolemic sub-group of hypertensives. CONCLUSIONS: Inflammatory markers of monocyte-endothelial cell adhesive interaction are elevated in hypertensives in comparison to normotensives and may be related to plasma ET-1 activity. The coexistence of hypercholesterolemia may enhance this inflammatory process induced by arterial hypertension.

Conduction patterns in the cardiac veins: electrophysiologic characteristics of the connections between left atrial and coronary sinus musculature.

INTRODUCTION: Fractionated electrograms and double potentials have been well described within the coronary sinus (CS) in humans. The pattern of circumferential activation in the CS has not been investigated. Furthermore, no data exist on conduction characteristics within the great cardiac vein (GCV) or the middle cardiac vein (MCV). METHODS AND RESULTS: Twenty patients underwent catheter mapping of the CS, the MCV, and the GCV. Anatomical areas were verified by cannulation of the left superior pulmonary vein. The pattern of circumferential muscle activation within the proximal CS was also studied with a circular mapping catheter (Lasso 12 mm). At conventional mapping during sinus rhythm and high right atrial pacing, discrete double potentials or fractionated electrograms were recorded during left, right atrial and CS pacing at the CS ostium, mid-CS, and distal CS-ligament of Marshall area, in 2 (10%), 1 (5%), and 9 (45%) patients, respectively, whereas no patient displayed such signals in the MCV or GCV ( p < 0.001). Proximal CS mapping with the Lasso was accomplished in 10 patients, 7 of whom had no evidence of multicomponent potentials in the CS at conventional mapping. Specific CS potentials dissociated from the atrial electrograms were recorded in all patiens with the use of circumferential mapping. The perimetric distribution of electrograms within the CS suggested an oblique course of conduction across the CS musculature. CONCLUSION: Potentials representing activation of the CS musculature, with an oblique course of conduction across the CS, can be recorded in human CS but not in the GCV or MCV. This is compatible with anatomical observations of sinus venosus musculature covering the CS but not other cardiac veins, and supports the rationale for the role of CS musculature in the generation of atrial arrhythmias.

Renal denervation for resistant hypertension: acute results and long-term follow-up.

INTRODUCTION: Renal sympathetic hyperactivity is vital for the maintenance and progression of essential hypertension. Catheter-based renal denervation is an evolving concept with favourable results regarding the control of hypertension; however, clinical experience is still limited. METHODS: We enrolled 15 patients with resistant hypertension who underwent percutaneous, catheter-based radiofrequency treatment for renal artery denervation. Patients were followed up for 4 to 13 months. RESULTS: Baseline mean blood pressure was 169/96 mmHg (SD 9/11), and patients were receiving a mean 3.9 ± 0.8 antihypertensive medications. Blood pressure values were reduced to 136/79 mmHg (SD 10/7), and antihypertensive medications to 2.9 ± 0.8 at 6.9 ± 3.4 months after the procedure. All procedures were uneventful and technically easy. The only drawbacks of the procedure are pain that the patient may feel during energy delivery, and the inability to obtain a sustained impedance reduction that allows completion of radiofrequency current delivery at some sites in the renal artery. CONCLUSIONS: Renal denervation facilitates control of resistant hypertension with reduction of medication, and appears to be a safe and technically easy procedure to accomplish.

A tachycardia with varying QRS morphology and RP intervals: differential diagnosis and therapy.

An interesting case of a tachycardia with varying QRS morphology and RP intervals is presented and the electrophysiological differential diagnosis is discussed.

Clinical and angiographic characteristics of patients with coronary artery ectasia.

BACKGROUND: The relationship of the extent of coronary artery ectasia (CAE) with coronary blood flow in the major epicardial arteries has not been adequately assessed. This study aimed at investigating the association of the topographical extent of CAE with coronary flow velocity and clinical characteristics in patients with isolated CAE and in patients with coexisting obstructive coronary artery disease (CAD). METHODS: We reviewed 3764 consecutive coronary angiograms performed at Athens Euroclinic and identified patients with CAE according to standard criteria. The topographical extent of ectasia was considered, and coronary flow velocity was determined using the TIMI frame count (TFC). The severity of CAD was assessed using the modified Gensini index and the number of diseased vessels. Clinical data were correlated with TFC and CAD severity analysis. RESULTS: Ectatic lesions were identified in 119 patients. The mean TFC correlated positively with the topographical extent of CAE (rs=0.733, p<0.001). Stepwise multiple linear regression revealed that the topographical extent of CAE and the maximum diameter of the ectatic segment in the corresponding artery are independent predictors of TFC in LAD and RCA. Using multivariate analysis, a history of myocardial infarction was independently associated with CAE extent, and CAD severity. CONCLUSIONS: The extent of ectasia in the coronary vasculature is correlated with coronary flow velocity and associated with clinical presentation independent of coexisting significant coronary stenoses.

Antiendothelial cell antibodies in patients with coronary artery ectasia.

BACKGROUND: The mechanisms involved in the pathogenesis of coronary artery ectasia (CAE) have not been elucidated. Circulating antiendothelial cell antibodies (AECA) are often detectable in systemic vasculitis and have been implicated in the pathogenesis of endothelial injury. Their prevalence in CAE is not known. METHODS AND RESULTS: Out of 475 consecutive patients subjected to coronary angiography, 27 patients were diagnosed with CAE. Thirty patients matched for age, body mass index, sex, and coronary artery disease prevalence, served as controls. Serum AECA of IgG, IgM, and IgA isotypes were detected using a cell-based enzyme-linked immunosorbent assay (ELISA). Antinuclear antibodies (ANA) and antineutrophil cytoplasmic antibodies (ANCA) were detected using indirect immunofluorescence. IgG and IgM anticardiolipin antibodies (aCL) were detected using commercial ELISA. The prevalence of ANA and ANCA was similar in CAE patients and controls (33.3 vs. 43.3%, and 3.3 vs. 7.4%, respectively). There was no significant difference in IgG or IgM aCL reactivity between patients and controls. Both CAE patients and controls were negative for IgG AECA. The frequency of IgM AECA positivity was similar in CAE patients and controls. The prevalence of AECA of the IgA isotype was significantly higher in CAE patients (37.0 vs. 10%, P<0.05). CONCLUSION: There is increased prevalence of circulating AECA of the IgA isotype in patients with CAE. This provides evidence for a role of autoimmunity in the pathogenesis of certain cases of CAE.

Slow-pathway ablation for atrioventricular nodal re-entrant tachycardia with no risk of atrioventricular block.

BACKGROUND: Slow-pathway ablation or modification eliminates typical atrioventricular nodal re-entrant tachycardia (AVNRT) but with a 1% risk of AV block. We report our experience from a series of consecutive patients with typical AVNRT who were ablated in our unit. METHODS: Consecutive patients (n=227), aged 22 to 56 years, 172 women, with slow-fast AVNRT underwent slow-pathway ablation. Mapping was restricted to the inferior part of the triangle of Koch, at the right or left septum, below the ostium of the coronary sinus, and was aimed at recording multicomponent, low-amplitude potentials. The endpoints of ablation were induction of a retrogradely conducted junctional rhythm, and non-inducibility of AVNRT on isoprenaline. RESULTS: All procedures were successful, with no change in the AH interval. Right-sided ablation was successful in 223 (98.2%) of cases. In four patients (1.8%) left-sided ablation was necessary. Procedure and fluoroscopy times were 70.1 ± 21.4 and 11.2 ± 5.8 min, respectively. In total, 4.5 ± 1.2 radiofrequency lesions per patient were given. During a follow-up period of one to three years, three patients (1.3%) had AVNRT recurrence. All of them had residual dual pathway physiology following ablation, while only 19.6% of patients without AVNRT had residual dual AV nodal conduction (p<0.001). No patient developed AV conduction disturbances. CONCLUSIONS: Ablation at the inferior part of the triangle of Koch with the protocol described offers a high success rate, with no risk of AV block, in patients with typical AVNRT. Residual dual AV nodal conduction carries an increased risk of AVNRT recurrence.

Stent thrombosis four and a half years after implantation of a sirolimus-eluting stent.

We report on a case of very late stent thrombosis, 51 months after implantation of a sirolimus-eluting stent and 15 months after clopidogrel discontinuation. This case underlines the possible need for long-term antiplatelet medication in patients receiving sirolimus-eluting stents.

Association of neutrophil gelatinase-associated lipocalin with the severity of coronary artery disease.

Serum neutrophil gelatinase-associated lipocalin (NGAL) concentrations were measured in 73 consecutive patients who underwent first-time angiography for suspected coronary artery disease (CAD), and their associations with angiographic indexes of the severity of CAD (i.e., number of diseased vessels and modified Gensini score) were estimated. Median serum NGAL levels in patients with angiographically confirmed CAD were significantly higher than those in patients with normal coronary arteries (29.0 ng/ml [interquartile range 25.2 to 36.8] vs 22.4 ng/ml [interquartile range 17.34 to 32.0], p = 0.004). Statistically significant correlations were observed between serum NGAL level and the number of diseased vessels (r(s) = 0.390, p = 0.01) and modified Gensini score (r(s) = 0.356, p = 0.002). Using multivariate analysis, serum NGAL level was independently associated with the presence and severity of CAD. In conclusion, serum NGAL levels are significantly higher in the presence of CAD and are correlated with the severity of the disease. Further clinical studies are needed to confirm the use of NGAL as a biomarker for the detection and extent of CAD.