X-Ray Magnetic Resonance Fusion to Internal Markers and Utility in Congenital Heart Disease Catheterization

OBJECTIVES: X-ray magnetic resonance fusion (XMRF) allows for utilization of 3D data during cardiac catheterization. However, to date, technical requirements have limited the use of this modality in clinical practice. Here we report on a new internal marker XMRF method that we have developed and describe how we used XMRF during cardiac catheterization in congenital heart disease.

METHODS: XMRF was performed in a phantom and in 23 patients presenting for cardiac catheterization who also needed cardiac MRI for clinical reasons. The registration process was performed in less than 5 minutes per patient with minimal radiation (0.004 – 0.024 mSv) and without contrast. Registration error was calculated in a phantom and in 8 patients using the maximum distance between angiographic and 3D model boundaries.

RESULTS: In the phantom the measured error in the AP projection had a mean of 1.15 mm (standard deviation 0.73). The measured error in patients had a median of 2.15 mm (IQR 1.65 – 2.56 mm). Internal markers included bones, airway, image artifact, calcifications, and the heart and vessel borders. The MRI data was used for road mapping in 17/23 (74%) cases and camera angle selection in 11/23 (48%) cases.

CONCLUSIONS: Internal markers based registration can be performed quickly, with minimal radiation, without the need for contrast, and with clinically acceptable accuracy using commercially available software. We have also demonstrated several potential uses for XMRF in routine clinical practice. This modality has the potential to reduce radiation exposure and improve catheterization outcomes.

PMID:

The Pathology of Neoatherosclerosis in Human Coronary Implants Bare-metal and Drug-Eluting Stents

OBJECTIVES: Human coronary bare-metal stents (BMS) and drug-eluting stents (DES) from autopsy cases with implant duration >30 days were examined for the presence of neointimal atherosclerotic disease.  Neointimal atherosclerotic change (neoatherosclerosis) after BMS implantation is rarely reported and usually occurs beyond 5 years. The incidence of neoatherosclerosis after DES implantation has not been reported.

METHODS: All available cases from the CVPath stent registry (n = 299 autopsies), which includes a total of 406 lesions-197 BMS, 209 DES (103 sirolimus-eluting stents [SES] and 106 paclitaxel-eluting stents [PES])-with implant duration >30 days were examined. Neoatherosclerosis was recognized as clusters of lipid-laden foamy macrophages within the neointima with or without necrotic core formation.

RESULTS: The incidence of neoatherosclerosis was significantly greater in DES lesions (31%) than BMS lesions (16%; p < 0.001). The median stent duration with neoatherosclerosis was shorter in DES than BMS (DES, 420 days [interquartile range [IQR]: 361 to 683 days]; BMS, 2,160 days [IQR: 1,800 to 2,880 days], p < 0.001). Unstable lesions characterized as thin-cap fibroatheromas or plaque rupture were more frequent in BMS (n = 7, 4%) than in DES (n = 3, 1%; p = 0.17), with relatively shorter implant durations for DES (1.5 ± 0.4 years) compared to BMS (6.1 ± 1.5 years). Independent determinants of neoatherosclerosis identified by multiple logistic regression included younger age (p < 0.001), longer implant durations (p < 0.001), SES usage (p < 0.001), PES usage (p = 0.001), and underlying unstable plaques (p = 0.004).

CONCLUSIONS: Neoatherosclerosis is a frequent finding in DES and occurs earlier than in BMS. Unstable features of neoatherosclerosis are identified for both BMS and DES with shorter implant durations for the latter. The development of neoatherosclerosis may be yet another rare contributing factor to late thrombotic events.

PMID: 21376502

Features of Disrupted Plaques by Coronary Computed Tomographic Angiography: Correlates With Invasively Proven Complex Lesions

PMID: 21262981

In Vivo Evaluation of Stent Patency by 64-Slice Multidetector CT Coronary Angiography: Shall We Do It or Not?

OBJECTIVES: The diagnostic performance of in-stent restenosis (ISR) by 64-slice multidetector CT coronary angiography (CTCA) has been reported to be influenced by multiple factors. We evaluated individual factors (stent diameter, material and strut thickness) and therefore determined the proper population for follow-up by using this modality.

METHODS: A total of 171 stents were evaluated in 83 consecutive patients with stents imaged with CTCA and conventional coronary angiography. The stent diameter ranged from 2.25 mm to 4.5 mm. 2 models of stainless steel (Taxus Liberte (Boston Scientific, US), 56 stents and Cypher Select (Cordis, US), 34 stents) and 2 models of cobalt alloy (Endeavor (Medtronic, US), 33 stents and Firebird2 (MicroPort, China), 48 stents) were included. By comparing to conventional coronary angiography, the image quality and diagnostic accuracy for ISR were evaluated.

RESULTS: The image quality of Taxus, Endeavor and Firebird are markedly better than Cypher in large caliber group (≧3.0 mm) (P < 0.001). Except for Cypher, all other stents with diameter ≧3.0 mm showed excellent diagnostic accuracy (sensitivity 100%, specificity 94.4-96% whereas stents with diameter <3.0 mm had poor diagnostic accuracy (sensitivity 100%, specificity 33.3-70%). Cypher is the stent with thickest strut in our study, and showed reduced image quality and diagnostic accuracy in all stent size, due to large number of unassessable stents. Among 16 binary ISR, 12 lesions were correctly diagnosed by CTCA while the other 4 lesions were unassessable. The main reason for low specificity in small caliber group is the large number of unassessable stents.

CONCLUIONS: CTCA has high diagnostic accuracy to identify ISR in selected stents with a diameter of ≧3.0 mm.

PMID: 21461883

Can Differences in Corrected Coronary Opacification Measured With Computed Tomography Predict Resting Coronary Artery Flow?

OBJECTIVES: A proof-of-concept study was undertaken to determine whether differences in corrected coronary opacification (CCO) within coronary lumen can identify arteries with abnormal resting coronary flow. Although computed tomographic coronary angiography can be used for the detection of obstructive coronary artery disease, it cannot reliably differentiate between anatomical and functional stenoses.

METHODS: Computed tomographic coronary angiography patients (without history of revascularization, cardiac transplantation, and congenital heart disease) who underwent invasive coronary angiography were enrolled. Attenuation values of coronary lumen were measured before and after stenoses and normalized to the aorta. Changes in CCO were calculated, and CCO differences were compared with severity of coronary stenosis and Thrombolysis In Myocardial Infarction (TIMI) flow at the time of invasive coronary angiography.

RESULTS: One hundred four coronary arteries (n = 52, mean age = 60.0 ± 9.5 years; men = 71.2%) were assessed. Compared with normal arteries, the CCO differences were greater in arteries with computed tomographic coronary angiography diameter stenoses ≥50%. Similarly, CCO differences were greater in arteries with TIMI flow grade <3 (0.406 ± 0.226) compared with those with normal flow (TIMI flow grade 3) (0.078 ± 0.078, p < 0.001). With CCO differences, abnormal coronary flow (TIMI flow grade <3) was identified with a sensitivity and specificity, positive predictive value, and negative predictive value of 83.3% (95% confidence interval [CI]: 57.7 to 95.6%), 91.2% (95% CI: 75.2% to 97.7%), 83.3% (95% CI: 57.7% to 95.6%), and 91.2% (95% CI: 75.2% to 97.7%), respectively. Accuracy of this method was 88.5% with very good agreement (kappa = 0.75, 95% CI: 0.55 to 0.94).

CONCLUSIONS: Changes in CCO across coronary stenoses seem to predict abnormal (TIMI flow grade <3) resting coronary blood flow. Further studies are needed to understand its incremental diagnostic value and its potential to measure stress coronary blood flow.

PMID: 21392642

Meta-analysis: Diagnostic Performance of Low-Radiation-Dose Coronary Computed Tomography Angiography

PMID: 21403076

Potential Role of Three-Dimensional Rotational Angiography and C-Arm CT for Valvular Repair and Implantation

Imaging modalities utilized in the interventional cardiology suite have seen an impressive evolution and expansion recently, particularly with regard to the recent interest in three-dimensional (3D) imaging. Despite this, the backbone of visualization in the catheterization laboratory remains two-dimensional (2D) X-ray fluoroscopy and cine-angiography.New imaging techniques under development, referred to as three-dimensional rotational angiography (RA) and C-arm CT, hold great promise for improving current device implantation and understanding of cardiovascular anatomy. This paper reviews the evolution of rotational angiography and advanced 3D X-ray imaging applications to interventional cardiology.

PMID: 21394614

Cancer Risk Related to Low-Dose Ionizing Radiation from Cardiac Imaging in Patients After Acute Myocardial Infarction

OBJECTIVES: Patients exposed to low-dose ionizing radiation from cardiac imaging and therapeutic procedures after acute myocardial infarction may be at increased risk of cancer.

METHODS:  Using an administrative database, we selected a cohort of patients who had an acute myocardial infarction between April 1996 and March 2006 and no history of cancer. We documented all cardiac imaging and therapeutic procedures involving low-dose ionizing radiation. The primary outcome was risk of cancer. Statistical analyses were performed using a time-dependent Cox model adjusted for age, sex and exposure to low-dose ionizing radiation from noncardiac imaging to account for work-up of cancer.

RESULTS: Of the 82 861 patients included in the cohort, 77% underwent at least one cardiac imaging or therapeutic procedure involving low-dose ionizing radiation in the first year after acute myocardial infarction. The cumulative exposure to radiation from cardiac procedures was 5.3 milli Sieverts (mSv) per patient-year, of which 84% occurred during the first year after acute myocardial infarction. A total of 12 020 incident cancers were diagnosed during the follow-up period. There was a dose-dependent relation between exposure to radiation from cardiac procedures and subsequent risk of cancer. For every 10 mSv of low-dose ionizing radiation, there was a 3% increase in the risk of age- and sex-adjusted cancer over a mean follow-up period of five years (hazard ratio 1.003 per milliSievert, 95% confidence interval 1.002-1.004).

CONCLUSIONS: Exposure to low-dose ionizing radiation from cardiac imaging and therapeutic procedures after acute myocardial infarction is associated with an increased risk of cancer.

PMID: 21324846

Transcatheter Approaches to Non-Valvar Structural Heart Disease

With advancement in transcatheter technology, numerous non-congenital structural heart lesions previously untreated, or treated with surgery are now amenable to transcatheter therapy. These therapies have centered on transcatheter valve replacement, however, other lesions are increasingly treated via the percutaneous approach. These procedures include patent foramen ovale closure, left atrial appendage occlusion, closure of post-infarct ventricular septal defects, occlusion of ruptured sinus of Valsalva aneurysm and treatment of paravalvar leaks. This review will outline indications for and approach to each of these procedures in the context of the current literature base with emphasis on pre- and intra-procedural imaging modalities.

PMID: 21331612

A Prospective Natural-History Study of Coronary Atherosclerosis

OBJECTIVES: Atherosclerotic plaques that lead to acute coronary syndromes often occur at sites of angiographically mild coronary-artery stenosis. Lesion-related risk factors for such events are poorly understood.

METHODS: In a prospective study, 697 patients with acute coronary syndromes underwent three-vessel coronary angiography and gray-scale and radiofrequency intravascular ultrasonographic imaging after percutaneous coronary intervention. Subsequent major adverse cardiovascular events (death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization due to unstable or progressive angina) were adjudicated to be related to either originally treated (culprit) lesions or untreated (nonculprit) lesions. The median follow-up period was 3.4 years.

RESULTS: The 3-year cumulative rate of major adverse cardiovascular events was 20.4%. Events were adjudicated to be related to culprit lesions in 12.9% of patients and to nonculprit lesions in 11.6%. Most nonculprit lesions responsible for follow-up events were angiographically mild at baseline (mean [±SD] diameter stenosis, 32.3±20.6%). However, on multivariate analysis, nonculprit lesions associated with recurrent events were more likely than those not associated with recurrent events to be characterized by a plaque burden of 70% or greater (hazard ratio, 5.03; 95% confidence interval [CI], 2.51 to 10.11; P<0.001) or a minimal luminal area of 4.0 mm² or less (hazard ratio, 3.21; 95% CI, 1.61 to 6.42; P=0.001) or to be classified on the basis of radiofrequency intravascular ultrasonography as thin-cap fibroatheromas (hazard ratio, 3.35; 95% CI, 1.77 to 6.36; P<0.001).

CONCLUSIONS: In patients who presented with an acute coronary syndrome and underwent percutaneous coronary intervention, major adverse cardiovascular events occurring during follow-up were equally attributable to recurrence at the site of culprit lesions and to nonculprit lesions. Although nonculprit lesions that were responsible for unanticipated events were frequently angiographically mild, most were thin-cap fibroatheromas or were characterized by a large plaque burden, a small luminal area, or some combination of these characteristics, as determined by gray-scale and radiofrequency intravascular ultrasonography.

PMID:

Long-Term Outcome and Impact of Surgery on Adults With Coronary Arteries Originating From the Opposite Coronary Cusp

OBJECTIVES: An anomalous coronary artery from the opposite sinus of Valsalva may increase sudden death risk in children and young adults, and surgical intervention is often recommended. The impact of this lesion when recognized in the adult and its management are ill defined.

METHODS: We reviewed 210, 700 cardiac catheterizations performed over a 35-year period at a single institution and identified 301 adults with an anomalous coronary artery from the opposite sinus of Valsalva, either anomalous right coronary artery from the left cusp or anomalous left main coronary artery from the right cusp. Patients were stratified by the pathway of the anomalous artery and the chosen treatment.

RESULTS: Among the 301 patients with anomalous coronary artery from the opposite sinus of Valsalva (0.14% of the cohort), 79% had anomalous right coronary artery from the left cusp, and 18% had an interarterial course (IAC). Patients with IAC were younger (52±13 versus 59±13 years; P=0.001) and more likely to undergo surgical intervention (52% versus 27%; P<0.001), but mortality was not increased with IAC. Among the 54 patients with IAC, 28 underwent surgical repair with no perioperative deaths. Patients evaluated since 2000 were significantly more likely to be referred for surgery (P=0.004). Surgical patients were more likely to have abnormal stress tests (90% versus 43%; P=0.01) and had more extensive atherosclerosis but less diabetes mellitus (0% versus 23%; P=0.01). Long-term survival at 10 years appeared similar in both groups.

CONCLUSIONS: In this single-center cohort study of patients with an anomalous coronary artery from the opposite sinus of Valsalva, surgical management appears to have been favored recently. Despite no perioperative mortality, a positive impact on long-term survival was not observed. The impact of surgery in older adults with anomalous coronary arteries arising from the opposite coronary sinus with IAC deserves further study.

PMID: 21200009

Identification of ADAMTS7 As a Novel Locus for Coronary Atherosclerosis and Association of ABO With myocardial Infarction in the Presence of Coronary Atherosclerosis: Two Genome-Wide Association Studies

OBJECTIVES: We tested whether genetic factors distinctly contribute to either development of coronary atherosclerosis or, specifically, to myocardial infarction in existing coronary atherosclerosis.

PMID: 21239051

Standardized Endpoint Definitions for Transcatheter Aortic Valve Implantation Clinical Trials: A Consensus Report from the Valve Academic Research Consortium

PMID:

High-resolution magnetic resonance myocardial perfusion imaging at 3.0-Tesla to detect hemodynamically significant coronary stenoses as determined by fractional flow reserve.

OBJECTIVES: The objective of this study was to compare visual and quantitative analysis of high spatial resolution cardiac magnetic resonance (CMR) perfusion at 3.0-T against invasively determined fractional flow reserve (FFR).

BACKGROUND: High spatial resolution CMR myocardial perfusion imaging for the detection of coronary artery disease (CAD) has recently been proposed but requires further clinical validation.

METHODS: Forty-two patients (33 men, age 57.4 ± 9.6 years) with known or suspected CAD underwent rest and adenosine-stress k-space and time sensitivity encoding accelerated perfusion CMR at 3.0-T achieving in-plane spatial resolution of 1.2 × 1.2 mm(2). The FFR was measured in all vessels with >50% severity stenosis. Fractional flow reserve <0.75 was considered hemodynamically significant. Two blinded observers visually interpreted the CMR data. Separately, myocardial perfusion reserve (MPR) was estimated using Fermi-constrained deconvolution.

RESULTS: Of 126 coronary vessels, 52 underwent pressure wire assessment. Of these, 27 lesions had an FFR <0.75. Sensitivity and specificity of visual CMR analysis to detect stenoses at a threshold of FFR <0.75 were 0.82 and 0.94 (p < 0.0001), respectively, with an area under the receiver-operator characteristic curve of 0.92 (p < 0.0001). From quantitative analysis, the optimum MPR to detect such lesions was 1.58, with a sensitivity of 0.80, specificity of 0.89 (p < 0.0001), and area under the curve of 0.89 (p < 0.0001).

CONCLUSIONS: High-resolution CMR MPR at 3.0-T can be used to detect flow-limiting CAD as defined by FFR, using both visual and quantitative analyses.

PMID: 21185504

Septal Pouch in the Left Atrium and Risk of Ischemic Stroke

OBJECTIVES: We sought to assess the association between the presence of a septal pouch in the left atrium and ischemic stroke. It has been suggested that the presence of a left septal pouch (LSP) may favor the stasis of blood and possibly result in thromboembolic complications. However, the embolic potential of an LSP is not known.

METHODS: The association between an LSP and risk of stroke was assessed using a population-based case-control study design. The presence of an LSP was assessed by transesophageal echocardiography in 187 patients >50 years of age with a first-ever ischemic stroke (96 men, mean age 70.6 ± 9.0 years) and in 157 control subjects matched to patients by age, sex, and race/ethnicity. The association between an LSP and risk of stroke was assessed after adjustment for other stroke risk factors.

RESULTS: Patients with LSPs were younger than control subjects (67.5 ± 9.1 years vs. 69.6 ± 8.8 years; p = 0.046), with a lower prevalence of hypertension (68.0% vs. 80.3%; p = 0.01). There were no differences in the prevalence of LSPs between stroke patients and control subjects (28.9% vs. 29.3%, respectively; p = 0.93). The subgroup of 69 patients (36.9%) with cryptogenic stroke showed a similar prevalence of LSPs (31.9% vs. 29.3%; p = 0.70). Multivariable analysis showed that the presence of an LSP was not associated with ischemic stroke (odds ratio: 1.09; 95% confidence interval: 0.64 to 1.85) or cryptogenic stroke (odds ratio: 1.41; 95% confidence interval: 0.71 to 2.78).

CONCLUSIONS: This study does not demonstrate evidence of the association of the presence of an LSP with ischemic stroke or cryptogenic stroke. The stroke risk associated with LSPs requires further evaluation in the younger stroke populations. The cofactors that may turn an LSP from an innocent bystander to a causative mechanism for stroke remains to be elucidated.

PMID: 21163457