Additive Role of Coronary Magnetic Resonance Angiography for the Evaluation of Coronary Artery Disease

Coronary magnetic resonance angiography (CMRA) allows a noninvasive assessment of the coronary anatomy without exposing the patients to radiation. It is also superior to coronary computed tomography angiography (CCTA) for the evaluation of luminal narrowing in heavily calcified coronary segments. We report a case with triple-vessel disease, but it could not be accurately assessed by CCTA because of calcification and lack of a significant perfusion defect or myocardial scarring on cardiac magnetic resonance imaging (MRI). However, whole-heart CMRA performed as part of the cardiac MRI protocol demonstrated significant triple-vessel disease with left main involvement, confirmed by subsequent invasive angiography with a fractional flow reserve measurement.

Predictors of Angiographic Restenosis after Intracoronary Stenting according to Stent Lumen Cross Sectional Area and Stent Length in Native Coronary Artery Lesions: An Intravascular Ultrasound Study

BACKGROUND: The adequate intravascular ultrasound (IVUS) criteria for stent optimization have not been determined in long coronary stenting. We evaluated the predictors of angiographic restenosis and compared that according to stent lumen cross-sectional area (CSA) and stent length between short (stent length or =20 mm) coronary stenting. METHODS: IVUS-guided coronary stenting was successfully performed in 285 consecutive patients with 304 native coronary lesions. Six-month follow-up angiogram was performed in 236 patients (82.8%) with 246 lesions (80.9%). Results were evaluated using conventional (clinical, angiographic, and IVUS) methodology. RESULTS: The overall angiographic restenosis rate was 22.8% (56/246)(short stent 17.6% vs long stent 32.2%, p=0.009). Using multivariate logistic regression analysis, the independent predictors of angiographic restenosis were the IVUS stent lumen CSA (odd ratio=1.51, 95% CI 1.18-1.92, p=0.001) and stent length (odd ratio=0.95, 95% CI 0.91-1.00, p=0.039). The angiographic restenosis rate was 54.8% in stent lumen CSA & 5.0 mm2 (short stent 37.5% vs long stent 73.3%, p=0.049), 27.4% between 5.0 and 7.0 mm2 (short stent 24.1% vs long stent 31.7%, p=0.409), 10.5% between 7.0 and 9.0 mm2 (short stent 10.0% vs long stent 12.5%, p=0.772), and 11.4% in stent lumen CSA > or =9.0 mm2 (short stent 10.4% vs long stent 13.3%, p=0.767)(p=0.001). CONCLUSIONS: Compared with short coronary stenting, long coronary stenting is effective treatment modality to cover long lesions with comparable long-term clinical outcomes in cases of stent lumen CSA > or =7.0 mm2. Regardless of the stent length, the most important factor determining the angiographic restenosis was the IVUS stent lumen CSA in relatively large coronary artery lesions.

Chronic Stent Recoil of Different Design of Stents: An Intravascular Ultrasound Study

BACKGROUND: The chronic stent recoil of Palmaz-Schatz stent was minimal. However, the chronic stent recoil of other types of stents has not been determined. We evaluated the chronic stent recoil of different design of stents. METHODS: Serial (after stent implantation and follow-up) intravascular ultrasound images using automatic transducer pullback devices were obtained in 70 native coronary artery lesions: slotted-tube design of Palmaz-Schatz stent 30 and NIR 10, sinusoidal ring design of GFX 20, and coil design of CrossFlex 10. Measurements of stent cross-sectional area (CSA) (4 image slices in Palmaz-Schatz stent and 7 image slices in GFX, NIR and CrossFlex) using computerized planimetry were performed. Stent CSA post-stenting and follow-up was compared to evaluate the chronic stent recoil of different designs of stent. The chronic stent recoil (%) was defined as (post-intervention-follow-up) stent CSAx100/post-intervention stent CSA. RESULTS: The changes of stent CSA between post-intervention and follow-up period were minimal in NIR stent, Palmaz-Schatz and GFX. However, there was significant reduction of stent CSA in CrossFlex stent. Compared with other types of stents, the changes of stent CSA were significantly larger in CrossFlex stent (p=0.001). The chronic stent recoil was significantly larger in CrossFlex stent than in other types of stents (4.0+/-6.0% vs 0.7+/-5.8% in GFX stent, 0.4+/-5.0% in Palmaz-Schatz and 0.3+/-3.0% in NIR, p=0.001, respectively). There were no significant differences of chronic stent recoil among GFX, NIR and Palmaz-Schatz stent. CONCLUSIONS: The chronic stent recoil was minimal in slotted-tube and sinusoidal ring designs of stent. However, there was significant chronic stent recoil in coil design of stent.

Immediate and Late Clinical and Angiographic Outcomes after GFX Coronary Stenting: Is High-Pressure Balloon Dilatation Always Necessary?

BACKGROUND AND OBJECTIVES: The GFX stent is a flexible, balloon-expansible stent made of sinusoidal element of stainless steel. The adjunct high-pressure balloon dilatations after stenting were usually recommended in routine stenting procedure. The aim of this study was 1) to evaluate the immediate and long-term clinical and angiographic outcomes and 2) to investigate the necessity of high-pressure balloon during GFX stenting. MATERIAL AND METHODS: One hundred seventy two consecutive patients underwent single 12 or 18 mm GFX stent implantation in 188 native coronary lesions. Two types of stenting technique were used: 1) stent size of a final stent-to-artery ratio of 1:1 (inflation pressure > 10 atm, usually 12-14 atm: high pressure group) and 2) stent size of 0.5 mm bigger than reference vessel (inflation pressure 10 atm, usually 9 atm: low pressure group). The adjunct high-pressure balloon dilatations were done only in cases of suboptimal results. RESULTS: The adjunct high-pressure balloon dilatation were required under angiographic guidance in 11 of 83 lesions (13%) in high pressure group and 7 of 105 lesions (7%) in low pressure group (p=0.203). Procedural success rate was 100%. There were no significant differences of in-hospital and long-term clinical events between 2 group. The overall angiographic restenosis rate was 17.7%: 18.4% in high pressure group and 17.1% in low pressure group (p=0.991). CONCLUSION: GFX stent is a safe and effective device with high procedural success rate and favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials may be needed to compare stenting techniques in GFX stent implantations.