Lucia Di Francesco

Coronary stenting after rotational atherectomy in calcified and complex lesions. Angiographic and clinical follow-up results.

BACKGROUND Treatment of calcified (in contrast to simple) lesions with PTCA has been associated with a lower success rate and more procedural complications. Rotablation can improve acute results, but the high restenosis rate remains a problem. The purpose of this study was to evaluate the clinical and angiographic outcome of patients with complex and calcified lesions treated with a combination of rotablation and stenting. METHODS AND RESULTS Seventy-five consecutive patients with 106 lesions had rotablation prior to coronary stenting. Intravascular ultrasound-guided stenting was used without subsequent anticoagulation in 93% of patients. Procedural success was achieved in 93.4% of lesions. Acute stent thrombosis occurred in two lesions (1.9%), and subacute stent thrombosis in one lesion (0.9%). Angiographic follow-up was performed in 82.5% of lesions at 4.6 +/- 1.9 months with an angiographic restenosis rate of 22.5%. Clinical follow-up was performed in all patients at 6.4 +/- 3 months; target lesion revascularization was needed in 18% of lesions; Q-wave myocardial infarction occurred in 1.3%, coronary bypass surgery in 4.0%, and death in 1.3%. CONCLUSIONS Optimal coronary stenting after rotablation in calcified and complex lesions can be performed with a high success rate, an acceptable rate of procedural complications, and a low rate of stent thrombosis. This approach was associated with a low incidence of angiographic restenosis compared with results usually obtained with other interventional strategies in calcified and complex lesion subsets.

Angiographic and clinical outcome following coronary stenting of small vessels : A comparison with coronary stenting of large vessels

OBJECTIVES Stent implantation reduces restenosis in vessels > or =3 mm compared with balloon angioplasty, but few data are available for stents implanted in vessels <3 mm. The aim of this study was to evaluate immediate and follow-up patient outcomes after stent implantation in vessels <3 mm compared to stent implantation in vessels > or =3 mm. METHODS Between March 1993 and May 1996, a total of 1,298 consecutive patients (1,673 lesions) underwent coronary stenting. The study population was divided into two groups based on angiographic vessel diameter. In case of multivessel stenting, patients were randomly assigned only one lesion. Group I included 696 patients (696 lesions) in whom stents were implanted in vessels > or =3 mm, and group II included 602 patients (602 lesions) in whom stents were implanted in vessels <3 mm. RESULTS There was no difference in procedural success (95.4% in group I and 95.9% in group II), or subsequent subacute stent thrombosis (1.5% in group I and 1.4% in group II, p=NS). The postprocedure residual diameter stenosis was 3.31+/-12.4% in group I and -2.45+/-16.2% in group II. Angiographic follow-up was performed in 75% of patients, restenosis occurred in 19.9% of patients in group I and 32.6% in group II (p <0.0001). Absolute lumen gain was significantly higher in group I compared to group II, but absolute late lumen loss was similar in the two groups (1.05+/-0.91 mm in group I vs. 1.11+/-0.85 mm in group II, p=NS). Subsequently, the loss index was more favorable in group I (0.45 vs. 0.56; p=0.0006). Independent predictors of freedom from restenosis by multivariate logistic regression in the total population were: larger baseline reference diameter (odds ratio 2.032 p=0.006), larger postprocedure minimal stent cross-sectional area (odds ratio 1.190, p=0.0001) and shorter lesions (odds ratio 1.037, p=0.01). At long-term clinical follow-up, patients with small vessels had a lower rate of event-free survival (63% vs. 71.3%, p=0.007). CONCLUSIONS Coronary stenting can be performed in small vessels with a high success rate and low incidence of stent thrombosis. However, the long-term angiographic and clinical outcome of patients undergoing stent implantation in small vessels is less favorable than that of patients with large vessels.

Subacute stent thrombosis and the anticoagulation controversy: changes in drug therapy, operator technique, and the impact of intravascular ultrasound.

Clinical trials have shown that stents are superior to other catheter-based coronary interventions in terms of reduced complications and improved long-term efficacy. With utilization of high-pressure balloon inflation and intravascular ultrasound (IVUS) guidance, stent implantation can now be performed safely without anticoagulation (i.e., with lower rates of stent thrombosis and vascular complications). In 2 recent prospective clinical trials, stent thrombosis occurred in 3.5% of cases despite anticoagulant therapy, which resulted in an average of 7% vascular and bleeding complications. Initial use of IVUS during traditional stent deployment showed that 80% of stents were underexpanded and led to the hypothesis that stent thrombosis might be decreased as a result of optimal stent placement under IVUS guidance without the need for anticoagulation. In a prospective clinical trial to test this hypothesis, three factors were found to reduce stent thrombosis: full stent expansion, complete apposition to the vessel wall, and full lesion coverage. Predictors of thrombotic risk in this era of high-pressure stent deployment without anticoagulation include low ejection fraction, residual dissections, slow flow, multiple stents per lesion, and smaller postprocedure stent luminal diameter. To optimize stent expansion, stent dilation should be performed using a mean inflation pressure of 18 atm with a noncompliant or minimally compliant balloon sized to the vessel being treated (B/V ratio = 1.1). Controversy still remains about the best poststent antiplatelet regimen, and results of a recent trial should indicate whether heparin coating provides additional protection from stent thrombosis.

Long-term Angiographic and Clinical Outcome of Patients Undergoing Multivessel Coronary Stenting

BACKGROUND Randomized clinical trials have shown that multivessel coronary angioplasty is feasible and provides similar long-term survival as bypass surgery in selected patients. However, the higher need for repeat intervention, in particular, coronary artery bypass graft surgery, remains a problem. The objective of this study was to test the hypothesis that multivessel stenting is safe and effective in reducing the need for repeat interventions, in particular, the need for bypass surgery. METHODS AND RESULTS Between March 1993 and June 1995, 100 consecutive patients (243 lesions) had multivessel coronary stenting. High-pressure stent optimization was used in all patients. Procedural success was achieved in 97% of lesions; 2 patients (2%) required emergency bypass surgery. Angiographic follow-up was obtained in 89% of patients at 5.2+/-2.5 months. Angiographic restenosis occurred in 22% of the lesions, but 37% of patients had > or = 1 lesion with restenosis. Clinical follow-up was obtained in all patients at 21 +/- 10 months: target lesion revascularization was needed in 30 patients (30%), repeat angioplasty in 28 patients (28%) and coronary bypass surgery in 2 patients (2%); the overall survival rate was 96% (2% noncardiac death). CONCLUSIONS Multivessel coronary stenting can be performed with high success rate and low need for emergency bypass surgery. Compared with historical results with multivessel percutaneous transluminal coronary angioplasty, patients who undergo multivessel stenting need less repeat interventions, in particular, less coronary bypass surgery and have similar long-term survival.

Intracoronary Angiotensin II Potentiates Coronary Sympathetic Vasoconstriction in Humans

BACKGROUND In humans with coronary artery disease, ACE inhibition attenuates coronary sympathetic vasoconstriction. Whether this is due to removal of angiotensin (Ang) II production or to a reduced bradykinin breakdown, however, is unknown. METHODS AND RESULTS In eight normotensive patients with angiographic evidence of mild left coronary artery lesions (< or = 50%), mean arterial pressure (MAP, intra-arterial catheter), heart rate (HR, ECG lead), coronary sinus blood flow (CBF, thermodilution method), and coronary vascular resistance (CVR, ratio between MAP and CBF) were measured before and during a 15-minute left intracoronary infusion of Ang II at a dose that had no direct coronary or systemic vasomotor effects. The same measurements were made before and during a 15-minute infusion of saline. A 2-minute cold pressor test (CPT) and a 45-second diving were performed at the end of either infusion period. These maneuvers were used because their coronary vasomotor effects are abolished by phentolamine and thus depend on sympathetic activation. During saline infusion, both CPT and diving caused a marked increase in MAP. HR increased with CPT and fell with diving. CBF increased in parallel to the MAP increase, with little change in CVR. The MAP and HR responses were similar during Ang II infusion, which, however, caused either no change or a reduction in CBF with a consequent marked increase in CVR with both CPT and diving. In four additional patients, the diameter of the stenotic vessels remained unchanged during the CPT performed under saline and Ang II infusion. CONCLUSIONS Ang II markedly enhances sympathetic influences on coronary circulation in humans, presumably by acting at the arteriolar level. This may explain the blunting effect of ACE inhibition on sympathetic coronary vasoconstriction in patients with coronary artery disease.

New approach to quantitative angiographic assessment after stent implantation.

The new generation quantitative angiographic systems apply the interpolated technique to calculate the reference diameter at the site of the stenosis by integrating measurements of the segments proximal and distal to the stenosis. After stent implantation these measurements can be misleading as the treated segment, which is frequently larger than the adjacent not stented segments, is included in the measurements. The consequence is an overestimation of the reference diameter and the residual diameter stenosis. The present study was performed to compare this conventional technique of measurement with a new method which excludes the stented segment for the calculation of the reference diameter. Fifty-two lesions treated with poorly radiopaque stents (56% Palmaz-Schatz, 28% NIR, 10% Gianturco-Roubin, 6% Wallstent) expanded at high pressure (> = or 16 atm) were analyzed according to the conventional and stent excluded method. After stent implantation the reference diameter was 3.39 +/- 0.48 mm with conventional measurements and 3.02 +/- 0.45 mm with the stent excluded method (P < 0.05). The corresponding % diameter stenosis was 13 +/- 9 for the conventional technique and 1 +/- 13 for the stent excluded analysis (P < 0.05). The new approach to quantitative coronary analysis after stenting provides higher accuracy in reference diameter calculations and allows a more appropriate matching of stented segments with adjacent normal segments.

Comparison of Angiographic and Clinical Outcomes of Coronary Stenting of Chronic Total Occlusions Versus Subtotal Occlusions

The objective of this study was to assess the short- and long-term outcome of patients undergoing coronary stenting for chronic total occlusions compared with a control patient population with nonocclusive stenoses. A total of 789 consecutive patients (1,043 lesions) underwent coronary stenting using a high-pressure stent optimization technique. The study population was divided into total occlusion group (94 consecutive patients [95 lesions] with chronic total occlusions) and subtotal occlusion group (695 consecutive patients [948 lesions] with nonocclusive stenoses). There was no difference in post-procedure angiographic minimum lumen diameter (3.13 +/- 0.48 vs 3.15 +/- 0.57 mm, p = 0.72) and minimum intrastent cross-sectional area by intravascular ultrasound (7.31 +/- 2.06 vs 7.64 +/- 2.53 mm2, p = 0.26) between the total and subtotal groups, respectively. Subacute thrombosis occurred in 2 patients (2.1%) in the total group compared with 9 patients (1.3%) in the subtotal group (p = 0.63). Angiographic restenosis occurred in 27% vs 22% (p = 0.40) and repeat angioplasty in 15% vs 13% (p = 0.62) in the total and subtotal groups, respectively. Thus, coronary stenting of chronic total occlusions after successful recanalization could be performed with a high success rate. In addition, the incidence of stent thrombosis, angiographic restenosis, and the need for target lesion revascularization is comparable to that of an unselected cohort of patients with nonocclusive stenoses.

Mechanical recanalization of total coronary occlusions with the use of a new guide wire

The mechanical approach in the recanalization of total coronary occlusions consisted of the use of a new 0.014-inch standard coronary guide wire with jointless spring coil design that improves steering characteristics and tip stiffness. In addition, a 0.014-inch soft tip wire with hydrophilic coating and low-profile 1.5 mm over-the-wire balloons were used. The first wire was used selectively in 86 patients to treat 95 total occlusions, of which 51 (54%) were older than 3 months. Unfavorable angiographic characteristics were present in 79 (83%) of 95 lesions. Overall crossing success was 71% (67 of 95 lesions). Complications were one coronary perforation with cardiac tamponade necessitating emergency bypass surgery. In conclusion, the mechanical approach with the use of the standard coronary guide wire with jointless spring coil design provides a high success rate in the recanalization of unfavorable total occlusions.

Focal wall overstretching after high-pressure coronary stent implantation does not influence restenosis

To determine if vessel wall overstretching during coronary stenting is associated with a higher restenosis rate, the intravascular ultrasound morphological evaluation was performed following ultrasound criteria. A total of 468 lesions with successful coronary Palmaz‐Schatz stenting guided by intravascular ultrasound were classified into the no overstretching group (n = 295) and the overstretching group (n = 147). There were 26 lesions not classifiable due to the poststent morphology. Balloon‐to‐vessel ratio was 1.12 ± 0.17 in the no focal overstretching group and 1.20 ± 0.20 in the overstretching group (P < 0.0002). Follow‐up angiogram was performed in 77% of no focal overstretching group and in 75% of the focal overstretching group. The restenosis rate of the no focal overstretching group was 19.8% and 20.9% in the focal overstretching group, respectively (P = 0.65). Focal overstretching was more frequent following balloon oversizing. No increase in restenosis rate, found in focal overstretched stented lesions, leads us to the hypothesis of a regulation of smooth‐muscle‐cell proliferation activated by the normalization of blood flow and of shear stress, when stent implantation succeeds in optimally improving the lumen. Cathet. Cardiovasc. Intervent. 48:24–30, 1999.

Focal stent collapse in a patient with systemic sclerosis

We report a patient with systemic sclerosis having implantation of a 35 mm beStent with immediate success but developing angina at follow-up. A focal stent collapse with focal hyperplasia in and outside the stent was documented by ultrasound after 2 mos. A 14mm Palmaz-Schatz stent was successfully deployed into the collapsed beStent, with good 6-mo angiographic result. The stent collapse was probably due to unequal distribution of radial forces and possibly reactive hyperplasia in this unique patient with systemic sclerosis.