On-pump beating heart coronary surgery for high risk patients requiring emergency multiple coronary artery bypass grafting.

BACKGROUND: Cardiopulmonary bypass (CPB) with aortic cross-clamping and cardioplegic arrest remains the method of choice for patients requiring standard myocardial revascularization. Therefore, very high-risk patients presenting with acute coronary syndrome, unstable angina, onset of cardiac decompensation and requiring emergency multiple myocardial revascularization, can have a poor outcome. The on-pump beating heart technique can reduce the mortality and the morbidity in such a selected group of patients and this report describes our clinical experience. METHODS: Out of 290 patients operated for CABG from January 2005 to January 2006, 25 (8.6%) selected high-risk patients suffering from life threatening coronary syndrome (mean age 69 +/- 7 years) and requiring emergency multiple myocardial revascularization, underwent on-pump beating heart surgery. The mean pre-operative left ventricle ejection fraction (LVEF) was 27 +/- 8%. The majority of them (88%) suffered of tri-vessel coronary disease and 6 (24%) had a left main stump disease. Nine patients (35%) were on severe cardiac failure and seven among them (28%) received a pre-operative intra-aortic balloon pump. The pre-operative EuroScore rate was equal or above 8 in 18 patients (73%). RESULTS: All patients underwent on-pump-beating heart coronary revascularization. The mean number of graft/patient was 2.9 +/- 0.6 and the internal mammary artery was used in 23 patients (92%). The mean CPB time was 84 +/- 19 minutes. Two patients died during the recovery stay in the intensive care unit, and there were no postoperative myocardial infarctions between the survivors. Eight patients suffered of transitorily renal failure and 1 patient developed a sternal wound infection. The mean hospital stay was 12 +/- 7 days. The follow-up was complete for all 23 patients survived at surgery and the mean follow-up time was 14 +/- 5 months. One patient died during the follow-up for cardiac arrest and 2 patients required an implantable cardiac defibrillator. One year after surgery they all had a standard trans-thoracic echocardiogram showing a mean LVEF rate of 36 +/- 11.8%. CONCLUSION: Standard on-pump arrested heart coronary surgery has higher mortality and morbidity in emergencies. The on-pump beating heart myocardial revascularization seems to be a valid alternative for the restricted and selected cohort of patients suffering from life threatening coronary syndrome and requiring multiple emergency CABG.

Navigator-gated coronary magnetic resonance angiography using steady-state-free-precession: comparison to standard T2-prepared gradient-echo and spiral imaging.

RATIONALE AND OBJECTIVES: Recent developments of magnetic resonance imaging enabled free-breathing coronary MRA (cMRA) using steady-state-free-precession (SSFP) for endogenous contrast. The purpose of this study was a systematic comparison of SSFP cMRA with standard T2-prepared gradient-echo and spiral cMRA. METHODS: Navigator-gated free-breathing T2-prepared SSFP-, T2-prepared gradient-echo- and T2-prepared spiral cMRA was performed in 18 healthy swine (45-68 kg body-weight). Image quality was investigated subjectively and signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and vessel sharpness were compared. RESULTS: SSFP cMRA allowed for high quality cMRA during free breathing with substantial improvements in SNR, CNR and vessel sharpness when compared with standard T2-prepared gradient-echo imaging. Spiral imaging demonstrated the highest SNR while image quality score and vessel definition was best for SSFP imaging. CONCLUSION: Navigator-gated free-breathing T2-prepared SSFP cMRA is a promising new imaging approach for high signal and high contrast imaging of the coronary arteries with improved vessel border definition.

Coronary magnetic resonance angiography for the detection of coronary stenoses.

BACKGROUND: An accurate, noninvasive technique for the diagnosis of coronary disease would be an important advance. We investigated the accuracy of coronary magnetic resonance angiography among patients with suspected coronary disease in a prospective, multicenter study. METHODS: Coronary magnetic resonance angiography was performed during free breathing in 109 patients before elective x-ray coronary angiography, and the results of the two diagnostic procedures were compared. RESULTS: A total of 636 of 759 proximal and middle segments of coronary arteries (84 percent) were interpretable on magnetic resonance angiography. In these segments, 78 (83 percent) of 94 clinically significant lesions (those with a > or = 50 percent reduction in diameter on x-ray angiography) were also detected by magnetic resonance angiography. Overall, coronary magnetic resonance angiography had an accuracy of 72 percent (95 percent confidence interval, 63 to 81 percent) in diagnosing coronary artery disease. The sensitivity, specificity, and accuracy for patients with disease of the left main coronary artery or three-vessel disease were 100 percent (95 percent confidence interval, 97 to 100 percent), 85 percent (95 percent confidence interval, 78 to 92 percent), and 87 percent (95 percent confidence interval, 81 to 93 percent), respectively. The negative predictive values for any coronary artery disease and for left main artery or three-vessel disease were 81 percent (95 percent confidence interval, 73 to 89 percent) and 100 percent (95 percent confidence interval, 97 to 100 percent), respectively. CONCLUSIONS: Among patients referred for their first x-ray coronary angiogram, three-dimensional coronary magnetic resonance angiography allows for the accurate detection of coronary artery disease of the proximal and middle segments. This noninvasive approach reliably identifies (or rules out) left main coronary artery or three-vessel disease.

Right coronary MR angiography at 7 T: a direct quantitative and qualitative comparison with 3 T in young healthy volunteers.

PURPOSE: To objectively compare quantitative parameters related to image quality attained at coronary magnetic resonance (MR) angiography of the right coronary artery (RCA) performed at 7 T and 3 T. MATERIALS AND METHODS: Institutional review board approval was obtained, and volunteers provided signed informed consent. Ten healthy adult volunteers (mean age ± standard deviation, 25 years ± 4; seven men, three women) underwent navigator-gated three-dimensional MR angiography of the RCA at 7 T and 3 T. For 7 T, a custom-built quadrature radiofrequency transmit-receive surface coil was used. At 3 T, a commercial body radiofrequency transmit coil and a cardiac coil array for signal reception were used. Segmented k-space gradient-echo imaging with spectrally selective adiabatic fat suppression was performed, and imaging parameters were similar at both field strengths. Contrast-to-noise ratio between blood and epicardial fat; signal-to-noise ratio of the blood pool; RCA vessel sharpness, diameter, and length; and navigator efficiency were quantified at both field strengths and compared by using a Mann-Whitney U test. RESULTS: The contrast-to-noise ratio between blood and epicardial fat was significantly improved at 7 T when compared with that at 3 T (87 ± 34 versus 52 ± 13; P = .01). Signal-to-noise ratio of the blood pool was increased at 7 T (109 ± 47 versus 67 ± 19; P = .02). Vessel sharpness obtained at 7 T was also higher (58% ± 9 versus 50% ± 5; P = .04). At the same time, RCA vessel diameter and length and navigator efficiency showed no significant field strength-dependent difference. CONCLUSION: In our quantitative and qualitative study comparing in vivo human imaging of the RCA at 7 T and 3 T in young healthy volunteers, parameters related to image quality attained at 7 T equal or surpass those from 3 T.

A simplified method of stabilization and hemostasis for minimally invasive coronary artery bypass.

We describe a simple method to achieve both hemostasis and stabilization of the left anterior descending coronary artery during minimally invasive coronary artery bypass grafting. This technique allows the surgeon to perform a precise anastomosis of the left internal mammary artery to the target vessel on a beating heart.

Noninvasive visualization of coronary artery endothelial function in healthy subjects and in patients with coronary artery disease.

OBJECTIVES: The goal was to test 2 hypotheses: first, that coronary endothelial function can be measured noninvasively and abnormal function detected using clinical 3.0-T magnetic resonance imaging (MRI); and second, that the extent of local coronary artery disease (CAD), in a given patient, is related to the degree of local abnormal coronary endothelial function. BACKGROUND: Abnormal endothelial function mediates the initiation and progression of atherosclerosis and predicts cardiovascular events. However, direct measures of coronary endothelial function have required invasive assessment. METHODS: The MRI was performed in 20 healthy adults and 17 patients with CAD. Cross-sectional coronary area and blood flow were quantified before and during isometric handgrip exercise, an endothelial-dependent stressor. In 10 severe, single-vessel CAD patients, paired endothelial function was measured in the artery with severe stenosis and the contralateral artery with minimal disease. RESULTS: In healthy adults, coronary arteries dilated and flow increased with stress. In CAD patients, coronary artery area and blood flow decreased with stress (both p </= 0.02). In the paired study, coronary artery area and blood flow failed to increase during exercise in the mildly diseased vessel, but both area (p = 0.01) and blood flow (p = 0.02) decreased significantly in the severely diseased, contralateral artery. CONCLUSIONS: Endothelial-dependent coronary artery dilation and increased blood flow in healthy subjects, and their absence in CAD patients, can now be directly visualized and quantified noninvasively. Local coronary endothelial function differs between severely and mildly diseased arteries in a given CAD patient. This novel, safe method may offer new insights regarding the importance of local coronary endothelial function and improved risk stratification in patients at risk for and with known CAD.

Feasibility and effectiveness of using coronary stents in the treatment of hepatic artery stenoses after orthotopic liver transplantation: preliminary report.

OBJECTIVE: Our aim is to evaluate the feasibility, efficacy, and patency of using coronary stents for the treatment of hepatic artery stenosis after liver transplantation. CONCLUSION: Hepatic artery stenosis after liver transplantation can be treated using coronary stents. The low rate of complication, high technical success, and 1-year patency rates are encouraging.

Profile order and time-dependent artifacts in contrast-enhanced coronary MR angiography at 3T: origin and prevention.

To enhance the clinical value of coronary magnetic resonance angiography (MRA), high-relaxivity contrast agents have recently been used at 3T. Here we examine a uniform bilateral shadowing artifact observed along the coronary arteries in MRA images collected using such a contrast agent. Simulations were performed to characterize this artifact, including its origin, to determine how best to mitigate this effect, and to optimize a data acquisition/injection scheme. An intraluminal contrast agent concentration model was used to simulate various acquisition strategies with two profile orders for a slow-infusion of a high-relaxivity contrast agent. Filtering effects from temporally variable weighting in k-space are prominent when a centric, radial (CR) profile order is applied during contrast infusion, resulting in decreased signal enhancement and underestimation of vessel width, while both pre- and postinfusion steady-state acquisitions result in overestimation of the vessel width. Acquisition during the brief postinfusion steady-state produces the greatest signal enhancement and minimizes k-space filtering artifacts.

Fat signal suppression for coronary MRA at 3T using a water-selective adiabatic T2 -preparation technique.

PURPOSE: To improve fat saturation in coronary MRA at 3T by using a spectrally selective adiabatic T2 -Prep (WSA-T2 -Prep). METHODS: A conventional adiabatic T2 -Prep (CA-T2 -Prep) was modified, such that the excitation and restoration pulses were of differing bandwidths. On-resonance spins are T2 -Prepared, whereas off-resonance spins, such as fat, are spoiled. This approach was combined with a CHEmically Selective Saturation (CHESS) pulse to achieve even greater fat suppression. Numerical simulations were followed by phantom validation and in vivo coronary MRA. RESULTS: Numerical simulations demonstrated that augmenting a CHESS pulse with a WSA-T2 -Prep improved robustness to B1 inhomogeneities and that this combined fat suppression was effective over a broader spectral range than that of a CHESS pulse in a conventional T2 -Prepared sequence. Phantom studies also demonstrated that the WSA-T2 -Prep+CHESS combination produced greater fat suppression across a range of B1 values than did a CA-T2 -Prep+CHESS combination. Lastly, in vivo measurements demonstrated that the contrast-to-noise ratio between blood and myocardium was not adversely affected by using a WSA-T2 -Prep, despite the improved abdominal and epicardial fat suppression. Additionally, vessel sharpness improved. CONCLUSION: The proposed WSA-T2 -Prep method was shown to improve fat suppression and vessel sharpness as compared to a CA-T2 -Prep technique, and to also increase fat suppression when combined with a CHESS pulse.

Myocardial flow reserve by Rb-82 cardiac PET improves the selection of patients eligible for invasive coronary angiography

Aim: We asked whether myocardial flow reserve (MFR) by Rb-82 cardiac PET improve the selection of patients eligible for invasive coronary angiography (ICA). Material and Methods: We enrolled 26 consecutive patients with suspected or known coronary artery disease who performed dynamic Rb-82 PET/CT and (ICA) within 60 days; 4 patients who underwent revascularization or had any cardiovascular events between PET and ICA were excluded. Myocardial blood flow at rest (rMBF), at stress with adenosine (sMBF) and myocardial flow reserve (MFR=sMBF/rMBF) were estimated using the 1-compartment Lortie model (FlowQuant) for each coronary arteries territories. Stenosis severity was assessed using computer-based automated edge detection (QCA). MFR was divided in 3 groups: G1:MFR<1.5, G2:1.5≤MFR<2 and G3:2≤MFR. Stenosis severity was graded as non-significant (<50% or FFR ≥0.8), intermediate (50%≤stenosis<70%) and severe (≥70%). Correlation between MFR and percentage of stenosis were assessed using a non-parametric Spearman test. Results: In G1 (44 vessels), 17 vessels (39%) had a severe stenosis, 11 (25%) an intermediate one, and 16 (36%) no significant stenosis. In G2 (13 vessels), 2 (15%) vessels presented a severe stenosis, 7 (54%) an intermediate one, and 4 (31%) no significant stenosis. In G3 (9 vessels), 0 vessel presented a severe stenosis, 1 (11%) an intermediate one, and 8 (89%) no significant stenosis. Of note, among 11 patients with 3-vessel low MFR<1.5 (G1), 9/11 (82%) had at least one severe stenosis and 2/11 (18%) had at least one intermediate stenosis. There was a significant inverse correlation between stenosis severity and MFR among all 66 territories analyzed (rho= -0.38, p=0.002). Conclusion: Patients with MFR>2 could avoid ICA. Low MFR (G1, G2) on a vessel-based analysis seems to be a poor predictor of severe stenosis severity. Patients with 3-vessel low MFR would benefit from ICA as they are likely to present a significant stenosis in at least one vessel.

High-resolution 3D whole-heart coronary MRA: a study on the combination of data acquisition in multiple breath-holds and 1D residual respiratory motion compensation.

OBJECT: To study a scan protocol for coronary magnetic resonance angiography based on multiple breath-holds featuring 1D motion compensation and to compare the resulting image quality to a navigator-gated free-breathing acquisition. Image reconstruction was performed using L1 regularized iterative SENSE. MATERIALS AND METHODS: The effects of respiratory motion on the Cartesian sampling scheme were minimized by performing data acquisition in multiple breath-holds. During the scan, repetitive readouts through a k-space center were used to detect and correct the respiratory displacement of the heart by exploiting the self-navigation principle in image reconstruction. In vivo experiments were performed in nine healthy volunteers and the resulting image quality was compared to a navigator-gated reference in terms of vessel length and sharpness. RESULTS: Acquisition in breath-hold is an effective method to reduce the scan time by more than 30 % compared to the navigator-gated reference. Although an equivalent mean image quality with respect to the reference was achieved with the proposed method, the 1D motion compensation did not work equally well in all cases. CONCLUSION: In general, the image quality scaled with the robustness of the motion compensation. Nevertheless, the featured setup provides a positive basis for future extension with more advanced motion compensation methods.

Clinical outcome following combination of cutting balloon angioplasty and coronary β-radiation for in-stent restenosis : a report from the RENO registry

RESUME : Actuellement la brachythérapie endovasculaire reste le seul traitement efficace pour la resténose intrastent. Malgré ceci, la limitation majeure de cette technique est la resténose aux extrémités du stent (effet de bord) due à une couverture incomplète par la source radioactive (geographical miss). Le ballon coupant et qui ne glisse pas pourrait limiter le barotraumatisme engendré par la dilatation et qui avec la diminution de la radiation aux extrémités de la source radioactive, est à la base du geographical miss. Cette étude prospective a pour but d'examiner l'efficacité du traitement de la resténose intrastent par la combinaison d'angioplastie avec cutting ballon et β - irradiation. Le registre « Radiation in Europe NOvoste » (RENO) inclut tous les patients traités par β - irradiation coronaire avec le système Beta-CathTM System (Novoste Corporation, Brussels, Belgium) n'ayant pas été inclus dans une autre étude randomisée. Un premier sous-groupe de ces patients (groupe 1, n=166), représente les patients traités par cutting ballon et β - irradiation intra coronaire. Ce groupe a été défini d'une manière prospective et les résultats cliniques à 6 mois ont été comparés par rapport aux autres patients qui ont reçu un traitement par dilatation coronaire conventionnelle et β - irradiation (groupe 2, n=712). A 6 mois de suivi, on a retrouvé une différence significative entre les 2 groupes par rapport à la nécessité d'une nouvelle revascularisation du vaisseau préalablement traité (10,2% de récidive dans le groupe 1 contre 16,6 % dans le groupe 2 , p=0,04). Le nombre d'événements cardiaques majeurs (mortalité, infarctus du myocarde et revascularisation) a également été diminué de manière significative (10,8% contre 19,2% ; />=0,01). Cette observation a été confirmée par une analyse multivariée qui indique un risque diminué pour les événements cardiaques majeurs à 6 mois, (rapport de côtes : 0,49 ; intervalle de confiance 0,27-0,88 ; p=0,02). Comparé à l'angioplastie coronarienne avec ballon conventionnel, l'utilisation de cutting ballon avant la β - irradiation dans le traitement de la resténose intrastent démontre une meilleure évolution clinique à 6 mois. ABSTRACT: At present, vascular brachytherapy is the only efficient therapy for in-stent restenosis. Nevertheless edge restenosis often relat¬ed to geographical miss has been identified as a major limitation of the technique. The non-slippery cutting balloon has the potential to limit vascular barotraumas which, together with low-dose irradiation at both ends of the radioactive source, are the prerequisite for geographical miss. This prospective study aimed to examine the efficacy of combining cut¬ting balloon angioplasty and brachytherapy for in-stent restenosis. The Radiation in Europe NOvoste (RENO) registry prospectively tracked all patients who had been treated by coronary β-radiation with the Beta-CathTM System (Novoste Corporation. Brussels, Belgium) but were not included in a randomized radiation trial, A subgroup of patients with in-stent restenosis treated by cutting balloon angioplasty and coronary β-radiation (group 1, n = 166) was prospectively defined, and clinical outcomes of patients at 6 months were compared with those of patients treated by conventional angioplasty and coronary β -radiation (group 2, n = 712). At 6-month follow-up, there was a significant difference between groups 1 and 2 in- target vessel revascularization (10.2% versus 16.6% respectively; p = 0.04) and in the incidence of major adverse clinical events (MACE) including, death, myocardial infarction, and revascularization (10.8% versus 19.2%; p= 0.01). This observation was confirmed by a multivariate analysis indicating a. lower risk for MACE at 6 months (odds ratio: 0.49; confidence intervals: 0.27-0.88; p = 0.02). Compared to conventional angioplasty, cutting balloon angio¬plasty prior to coronary beta-radiation with the Beta-CathTM System seems to improve the 6-month clinical outcome in patients with in-stent restenosis.

Use of 2D Sensitivity Encoding for Slow-Infusion Contrast-Enhanced Isotropic 3-T Whole-Heart Coronary MR Angiography.

OBJECTIVE. The purpose of this study was to improve the blood-pool signal-to-noise ratio (SNR) and blood-myocardium contrast-to-noise ratio (CNR) of slow-infusion 3-T whole-heart coronary MR angiography (MRA).SUBJECTS AND METHODS. In 2D sensitivity encoding (SENSE), the number of acquired k-space lines is reduced, allowing less radiofrequency excitation per cardiac cycle and a longer TR. The former can be exploited for signal enhancement with a higher radiofrequency excitation angle, and the latter leads to noise reduction due to lower data-sampling bandwidth. Both effects contribute to SNR gain in coronary MRA when spatial and temporal resolution and acquisition time remain identical. Numeric simulation was performed to select the optimal 2D SENSE pulse sequence parameters and predict the SNR gain. Eleven patients underwent conventional unenhanced and the proposed 2D SENSE contrast-enhanced coronary MRA acquisition. Blood-pool SNR, blood-myocardium CNR, visible vessel length, vessel sharpness, and number of side branches were evaluated.RESULTS. Consistent with the numeric simulation, using 2D SENSE in contrast-enhanced coronary MRA resulted in significant improvement in aortic blood-pool SNR (unenhanced vs contrast-enhanced, 37.5 +/- 14.7 vs 121.3 +/- 44.0; p < 0.05) and CNR (14.4 +/- 6.9 vs 101.5 +/- 40.8; p < 0.05) in the patient sample. A longer length of left anterior descending coronary artery was visualized, but vessel sharpness, coronary artery coverage, and image quality score were not improved with the proposed approach.CONCLUSION. In combination with contrast administration, 2D SENSE was found effective in improving SNR and CNR in 3-T whole-heart coronary MRA. Further investigation of cardiac motion compensation is necessary to exploit the SNR and CNR advantages and to achieve submillimeter spatial resolution.

Improved coronary artery definition with T2-weighted, free-breathing, three-dimensional coronary MRA.

BACKGROUND: Three-dimensional (3D) navigator-gated and prospectively corrected free-breathing coronary magnetic resonance angiography (MRA) allows for submillimeter image resolution but suffers from poor contrast between coronary blood and myocardium. Data collected over >100 ms/heart beat are also susceptible to bulk cardiac and respiratory motion. To address these problems, we examined the effect of a T2 preparation prepulse (T2prep) for myocardial suppression and a shortened acquisition window on coronary definition. METHODS AND RESULTS: Eight healthy adult subjects and 5 patients with confirmed coronary artery disease (CAD) underwent free-breathing 3D MRA with and without T2prep and with 120- and 60-ms data-acquisition windows. The T2prep resulted in a 123% (P<0. 001) increase in contrast-to-noise ratio (CNR). Coronary edge definition was improved by 33% (P<0.001). Acquisition window shortening from 120 to 60 ms resulted in better vessel definition (11%; P<0.001). Among patients with CAD, there was a good correspondence with disease. CONCLUSIONS: Free-breathing, T2prep, 3D coronary MRA with a shorter acquisition window resulted in improved CNR and better coronary artery definition, allowing the assessment of coronary disease. This approach offers the potential for free-breathing, noninvasive assessment of the major coronary arteries.