Clopidogrel-associated TTP: an update of pharmacovigilance efforts conducted by independent researchers, pharmaceutical suppliers, and the Food and Drug Administration

BACKGROUND AND PURPOSE

Since the 1999 identification of clopidogrel-associated thrombotic thrombocytopenic purpura (TTP) through independent active surveillance, subsequent cases have been identified by pharmaceutical suppliers of clopidogrel and the Food and Drug Administration (FDA). For cases of clopidogrel-associated TTP reported between 1998 to 2002, we evaluated the quality and timeliness of data from 3 reporting systems-independent active surveillance (n=13), pharmaceutical suppliers (n=24), and the FDA (n=13)-and identified prognostic factors associated with mortality.

METHODS

This study assessed the completeness of information on TTP diagnosis, treatment response, and causality from the 3 reporting systems. In addition, predictors of mortality were identified through classification tree analysis.

RESULTS

Completeness, timeliness, and certainty of diagnosis were best for cases obtained by active surveillance, intermediate for cases reported to the pharmaceutical supplier, and poorest for cases reported directly to the FDA. Clopidogrel had been used for </=2 weeks by 65%. The survival rate for patients with clopidogrel-associated TTP was 71.2%. Receipt of therapeutic plasma exchange within 3 days of onset of TTP increased the likelihood of survival (100% versus 27.3%, P<0.001).

CONCLUSIONS

Compared with reports submitted by suppliers or the FDA, reports obtained through active surveillance provided timelier and more complete information. Clopidogrel-associated TTP often occurs within 2 weeks of drug initiation, occasionally relapses, and has a high mortality if not treated promptly.

Angiographically silent left main disease detected by intravascular ultrasound: a marker for future adverse cardiac events

BACKGROUND

Concomitant moderate obstructive left main (LM) disease is associated with future cardiac events and poor prognosis in patients undergoing percutaneous intervention (PCI). Whether prognosis is similarly effected by LM disease not detected by angiography, but evident on intravascular ultrasound (IVUS) imaging, is not known. The purpose of this study was to evaluate the long-term prognosis of patients with angiographically insignificant LM coronary artery disease undergoing PCI.

METHODS AND RESULTS

One hundred and seven consecutive patients undergoing PCI with angiographically normal or mild LM disease had 2- and 3-dimensional IVUS imaging. IVUS images were digitized, and 3-dimensional reconstruction was performed. Percent diameter and area stenosis by angiography were 4.8% +/- 3.5% and 18.2% +/- 9.8%, respectively. IVUS mean luminal area and area stenosis were 17.9 +/- 5.6 mm2 and 30.2% +/- 14.7%, respectively. Long-term follow-up was available in 102 (95%) patients at a median of 29 (range 8-52) months. Major adverse cardiac events, defined as death (6), myocardial infarction (4), repeat PCI (13), or CABG (16), were associated with female sex (P =.04), diabetes (P =.02), angiographic minimum lumen diameter (P =.04), and IVUS minimum (P =.01) and mean (P =.01) lumen area. Multivariate predictors of late cardiac events were diabetes (hazard ratio 2.69, P =.014) and minimum lumen area by IVUS (hazard ratio 0.59, P =.015).

CONCLUSIONS

Despite being angiographically silent, LM disease detected by IVUS is an independent predictor of cardiac events and may serve as a marker for such events. These data extend the spectrum of LM disease severity and its relationship to cardiac prognosis in patients undergoing PCI.

450 million years of hemostasis

In mammalian blood coagulation, five proteases (factor VII [FVII]; factor IX [FIX]; factor X [FX]; protein C [PC] and prothrombin [PT]) act with five cofactors (tissue factor [TF]; factor V [FV]; factor VIII [FVIII]; thrombomodulin and protein S) to control the generation of fibrin. Biochemical evidence, molecular cloning data and comparative sequence analysis support the existence of all components of this network in all jawed vertebrates, and strongly suggest that it evolved before the divergence of teleosts over 430 million years ago. Phylogenetic analysis of the amino acid sequences of the Gla-EGF1-EGF2-SP domain serine proteases (FVII, FIX, FX, PC) and the A domain-containing cofactors (FV and FVIII) strongly supports the evolution of the blood coagulation network through two rounds of gene duplication, and supports the hypothesis that vertebrate evolution benefited from two global genome duplications. The jawless vertebrates (hagfish and lamprey) that diverged over 450 million years ago have a blood coagulation network involving TF, PT and fibrinogen. Preliminary evidence indicates that they may have a smaller complement of Gla-EGF1-EGF2-SP domain proteins, suggesting the existence of a 'primitive' coagulation system in jawless vertebrates.

Troponin I elevation and cardiac events after percutaneous coronary intervention

BACKGROUND

Serum troponins are sensitive markers of myonecrosis and ischemia and are now widely used in clinical practice. Although percutaneous coronary intervention (PCI)-related creatine kinase-myocardial band isoenzyme (CK-MB) elevation has been associated with future cardiac events, the significance of troponin elevation in this setting is unknown. We sought to determine whether serum troponin I (Tn-I) elevation after PCI is associated with future cardiac events. Methods and Results Consecutive patients undergoing elective PCI underwent systematic postprocedure measurement of Tn-I and CK-MB levels. Serum levels were correlated with demographic, angiographic, and procedural characteristics and the development of major adverse cardiac events (MACE; defined as death, MI, or need for PCI or coronary bypass graft surgery) at 30 days, 6 months, and 1 year. In 286 consecutive procedures, postintervention myonecrosis-specific Tn-I was elevated in 13.6% of patients, and CK-MB was elevated in 12.9% of patients. Multivariable predictors of Tn-I elevation were procedural side branch occlusion and thrombus formation. Peak Tn-I and CK-MB values were well correlated (r = 0.81, P <.0001). Three-fold elevation of Tn-I after successful PCI was independently predictive of MACE (P =.01).

CONCLUSIONS

Tn-I elevation after elective PCI is relatively common and is associated with procedural complications such as incidental side branch occlusion and thrombus formation. In addition, this study demonstrates that a 3-fold elevation of Tn-I after successful elective PCI is predictive of future cardiac events, especially the need for early repeat revascularization.

Post-cardiac catheterization access site complications and low-molecular -weight heparin following cardiac catheterization

The low molecular weight heparin enoxaparin is often administered to patients on long-term anticoagulation regimens who temporarily discontinue warfarin prior to undergoing invasive procedures. The clinical outcome of all enoxaparin-treated patients who underwent cardiac catheterization or coronary artery interventional procedures (n = 119) was evaluated. A total of 5 patients (4.2%) requiring anticoagulation (3 with chronic atrial fibrillation and 2 with ventricular thrombi) developed severe late enoxaparin-associated hemorrhagic or vascular complications at the femoral arterial puncture site between 3 and 11 days post-procedure. Complications included development of femoral arterial pseudoaneurysm (n = 3), hypotension (systolic blood pressure < 90 mmHg) (n = 2), acute decrease in hemoglobin levels to < 8.5 mg/dl (n = 4) and cardiac arrest (n = 1). In patients receiving standard dose enoxaparin after percutaneous invasive cardiac procedures, there is the potential for delayed and severe access site hemorrhagic and vascular complications.

A comparison of arterial closure devices to manual compression in liver transplantation candidates undergoing coronary angiography

Whether arterial closure devices can be used safely in a coagulopathic population undergoing cardiac catheterization and at high risk for groin complications, such as liver transplant candidates, is unknown. In this prospective, non-randomized consecutive series of 80 liver transplant candidates undergoing coronary angiography, manual compression and arterial closure devices were compared. Ilio-femoral angiography was performed to determine suitability for use of the closure device. Bleeding and vascular complications were recorded along with time to ambulation. Arterial closure devices were used in 31 patients (39%), whereas manual compression was used in 49 patients (50 procedures) (61%). There were no significant differences between the two groups with respect to age, sex, cardiac risk factors, peripheral vascular disease, baseline platelet count or baseline INR. There were 10 total vascular complications out of 50 procedures (20%) in the manual compression group compared to 2 vascular complications out of 31 procedures in the arterial closure device group (6%; p = 0.12). The time to ambulation was significantly less in the group receiving arterial closure devices versus manual compression (4.2 1.8 hours versus 6.6 3.7 hours, respectively; p = 0.0003). In coagulopathic patients at higher risk for groin complications, arterial closure devices can be safely used and decrease time to ambulation compared to manual compression.

Recent clinical trials of iodixanol

In patients with well-preserved renal function, the choice of contrast agent appears to have little impact on the development of contrast-induced nephropathy (CIN). However, in patients with underlying renal insufficiency and diabetes mellitus, it has been shown that the use of low-osmolar media is associated with a lower incidence of CIN compared with high-osmolar agents. Previously, it was unknown whether further benefit would be derived from the use of iso-osmolar contrast media. Recent studies, including Nephrotoxicity in High-Risk Patients Study of Iso-osmolar and Low-Osmolar Nonionic Contrast Media (NEPHRIC), have shown a reduction in the incidence of CIN with the iso-osmolar contrast agent iodixanol compared with low-osmolar agents in patients with renal insufficiency and diabetes. The peak rise in serum creatinine was significantly reduced with iodixanol (0.13 mg/dL vs 0.55 mg/dL, P <.001). The incidence of CIN, defined as a peak rise > 0.5 mg/dL, was decreased from 26% to 3%, P <.0002 when iodixanol was used. An ongoing, multicenter, prospective, double-blind, randomized study (Visipaque Angiography/Interventions with Laboratory Outcomes for Renal Insufficiency [VALOR]) is evaluating the potential benefit of iodixanol in reducing CIN in patients with preexisting renal impairment. Accumulating evidence suggests that the use of iso-osmolar contrast agents in conjunction with other proven measures, especially adequate intravenous hydration and contrast dosage limitation, can reduce the morbidity and mortality associated with CIN. These measures have the potential for a significant reduction in health care costs.

Spontaneous multivessel coronary artery dissection in a long-distance runner successfully treated with oral antiplatelet therapy

Spontaneous coronary artery dissection is an unusual yet clinically important cause of acute coronary syndromes. We present the case of a 37-year-old woman, actively training for a marathon, who presented with a non-Q wave myocardial infarction due to multivessel spontaneous coronary artery dissection, along with a review of the literature on spontaneous coronary artery dissections manifesting as acute myocardial infarctions.

Clinical pharmacology of higher dose eptifibatide in percutaneous coronary intervention (the PRIDE study)

This study describes the dose-exploration phase of the PRIDE trial, an investigation of the clinical pharmacology of higher dose eptifibatide in patients who underwent elective percutaneous coronary intervention (PCI). Outcomes of treatment with the platelet glycoprotein IIb/IIIa inhibitors were dependent upon proper dosing selection. In this multicenter, placebo-controlled clinical study, 127 patients were randomized 1:1:2:2 into 1 of the following treatment groups: placebo; eptifibatide as a 135 microg/kg bolus followed by a 0.75 microg/kg/min infusion; eptifibatide as a 180 microg/kg bolus with a 2.0 microg/kg/min infusion; or eptifibatide as a 250 microg/kg bolus with a 3.0 microg/kg/min infusion. Light transmission aggregometry was used to determine platelet aggregation in response to 20 microM adenosine diphosphate, and platelet receptor occupancy was also determined. Eptifibatide exhibited linear pharmacokinetics over the dose range studied. Inhibition of platelet aggregation was greater in samples collected in sodium citrate compared with those collected in D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone. The 180/2.0 dosing regimen achieved 90% inhibition of platelet aggregation immediately (5 minutes) and at steady state (8 to 24 hours). At 1 hour, mean inhibition of platelet aggregation was 80%. Eptifibatide exhibited dose-dependent pharmacodynamics that were dependent upon choice of anticoagulant. A 180 microg/kg bolus followed by a 2.0 microg/kg/min infusion at steady state achieved >80% inhibition of platelet aggregation. With the single-bolus regimen, however, there was an early loss of the inhibition of platelet aggregation before steady state was reached. Additional dose-exploration studies may further optimize eptifibatide dosing.

Predictors of long-term outcomes following direct percutaneous coronary intervention for acute myocardial infarction

To determine predictors of a long-term major adverse cardiac event (MACE) in unselected patients undergoing direct percutaneous coronary intervention (PCI), 274 consecutive patients presenting within 12 hours of ST-segment elevation acute myocardial infarction (AMI) were evaluated. No patient with ST-segment elevation AMI received intravenous thrombolytic drugs. Chest pain to balloon time was 3.8 hours (range 2.5 to 6.9). percutaneous transluminal coronary angioplasty was successful in 95% of patients. Abciximab was administered to 69% of patients, stents were deployed in 53%, and 17% underwent only catheterization. In-hospital events were death (7%), abrupt closure (2%), emergent coronary artery bypass grafting (CABG) (5%), repeat PCI (3%), and recurrent myocardial infarction (1%). In patients undergoing direct PCI (n = 227), the in-hospital event rate was death 5.3%, abrupt closure 2.2%, emergency CABG 0.9%, repeat PCI 3.1%, and repeat myocardial infarction 1.3%. Median time to last follow-up or death was 20 months (range 11 to 34), and to any event, 0.3 months (range 0.03 to 24.0). Postdischarge MACE included death (5%), AMI (4%), repeat PCI (8%), CABG (9%), and stroke (0.7%). Among those undergoing direct PCI (n = 227), 10% died, 3.5% had a repeat AMI, 9% had a repeat PCI, 5% had CABG, and 1% had a stroke at long-term follow-up. At long-term follow-up, 75% were event free. Multivariate predictors were (hazard ratio [95% confidence interval (CI)]): abciximab use 0.6 (95% CI 0.43 to 0.95), Killip class 2.2 (95% CI 1.1 to 4.4), and number of narrowed coronary arteries 1.7 (95% CI 1.4 to 2.2). In this unselected consecutive series of patients presenting with ST-segment elevation AMI, direct PCI was associated with sustained long-term efficacy. Outcomes were predicted by cardiac impairment at presentation and number of narrowed coronary arteries. MACE is not related to device selection but is significantly improved with abciximab.

In-hospital and long-term outcomes of patients with acute myocardial infarction undergoing direct angioplasty during regular and after hours

Off-hours presentation resulted in a significant increase in the onset of pain to balloon inflation time (approximately 1.3 hours) as well as the emergency room to balloon inflation time (approximately 54 minutes). However, this delay to reperfusion did not result in a difference in clinical outcomes (in-hospital or long-term) in patients undergoing direct percutaneous transluminal coronary angioplasty within 12 hours of the onset of acute myocardial infarction.

Adjunctive therapies in the cath lab. Successful thrombolysis using the combination of tissue plasminogen activator and abciximab in an adult with Kawasaki's disease

Kawasaki's disease is an acute systemic vasculitic syndrome that primarily affects children. Coronary aneurysms are common vasculitic sequelae of Kawasaki's disease. Intracoronary thrombosis and embolization are potential consequences of coronary aneurysms. We describe our experience of successful thrombolysis using the combination of reduced-dose intravenous tissue plasminogen activator and abciximab as described in the Thrombolysis in Myocardial Infarction 14 trial (TIMI 14) to treat a patient found to have intracoronary thrombus at the site of aneurysm formation due to Kawasaki's disease.

Excimer laser facilitated percutaneous coronary intervention of a nondilatable coronary stent

A patient is described in which excimer laser percutaneous coronary intervention is performed inside a suboptimally expanded stent due to nondilatable calcified plaque. The use of excimer laser facilitated full expansion of the stent with a balloon.

Resource utilization and clinical outcomes of coronary stenting: a comparison of intravascular ultrasound and angiographical guided stent implantation

BACKGROUND

Intravascular ultrasound (IVUS) guided stent implantation studies have demonstrated that inadequate stent implantation can occur despite achieving an optimal angiographic result. Furthermore, IVUS-guided stent implantation has been shown to improve lesional acute gain. However, it is unknown whether the use of IVUS guidance during stent implantation is associated with improved acute and long-term clinical outcomes. Moreover, the additional procedural cost and time incurred with the use of IVUS-directed stent implantation has not been evaluated. Thus the purpose of this study was to determine whether IVUS-guided stent implantation is associated with improved clinical outcomes compared with angiographically guided stent implantation and to evaluate the difference in resource utilization between these respective stent deployment strategies.

METHODS

Data were collected on 278 consecutive patients in whom 455 stents were deployed in native coronary arteries. High-pressure (> or = 12 atm) balloon inflations were performed until an optimal angiographic result was obtained. In the angiographically guided group, no IVUS imaging was performed. In the IVUS-guided group, IVUS imaging and additional interventions were performed attempting to achieve full apposition, absence of edge tear, and acute gain (lesion lumen area: distal reference lumen area) > or = 0.8 in subsequent IVUS imaging. Total procedure time, fluoroscopy time, contrast media volume, number of balloons, stents, guidewires, guide catheters, and procedural cost were calculated. In hospital abrupt closure rate and 6-month major adverse cardiovascular events (cardiac death, myocardial infarction, target vessel revascularization) rate were obtained.

RESULTS

A total of 178 patients underwent IVUS-guided stent placement and 100 patients underwent angiographically guided stent implantation. There was no significant difference in procedure time (107 +/- 49 vs 100 +/- 50 minutes, P = .22), fluoroscopy time (33 +/- 24 vs 30 +/- 18 minutes, P = .36), contrast volume (411 +/- 157 vs 386 +/- 181 mL, P = .23), guide catheters (1.3 +/- 0.8 vs 1.3 +/- 0.6, P = .69), guidewires (1.6 +/- 1.2 vs 1.6 +/- 1.0, P = .99), balloons (2.4 +/- 1.0 vs 2.3 +/- 1.3, P = .58), and stents (1.7 +/- 0.9 vs 1.6 +/- 0.9, P = .42). Intraprocedural cost was significantly higher in the IVUS-guided group, $4142 +/- 1547 verus $3635 +/- 1949 (P = .03), which was primarily related to the cost of the IVUS catheter. However, the in-hospital acute vessel closure rate was significantly lower in the IVUS-guided group, 0.6% versus 4% (P = .04). There was a trend toward lower target vessel revascularization rate in the IVUS-guided group (11% vs 19%, P = .08). By multivariate analysis IVUS use was demonstrated to be an independent negative predictor of cardiac death, myocardial infarction, repeat revascularization, and abrupt stent closure with a relative risk of 0.49 (95% confidence interval of 0.25 to 0.98), and P = .04.

CONCLUSIONS

The use of IVUS guidance during stent implantation does not significantly increase procedure time, fluoroscopy exposure, contrast volume, or device utilization. Furthermore, despite the increase in procedural cost, IVUS-guided stent implantation is associated with a significant decrease in the in-hospital abrupt closure rate and a trend toward a lower 6-month target vessel revascularization.

Visualization of discrete microinfarction after percutaneous coronary intervention associated with mild creatine kinase-MB elevation

BACKGROUND

Mild elevations in creatine kinase-MB (CK-MB) are common after successful percutaneous coronary interventions and are associated with future adverse cardiac events. The mechanism for CK-MB release remains unclear. A new contrast-enhanced MRI technique allows direct visualization of myonecrosis.

METHODS AND RESULTS

Fourteen patients without prior infarction underwent cine and contrast-enhanced MRI after successful coronary stenting; 9 patients had procedure-related CK-MB elevation, and 5 did not (negative controls). The mean age of all patients was 61 years, 36% had diabetes, 43% had multivessel coronary artery disease, and all had a normal ejection fraction. Twelve patients (86%) received an intravenous glycoprotein IIb/IIIa inhibitor; none underwent atherectomy, and all had final TIMI 3 flow. Of the 9 patients with CK-MB elevation, 5 had a minor side branch occlusion during stenting, 2 had transient ECG changes, and none developed Q-waves. The median CK-MB was 21 ng/mL (range, 12 to 93 ng/mL), which is 2.3x the upper limit of normal. Contrast-enhanced MRI demonstrated discrete regions of hyperenhancement within the target vessel perfusion territory in all 9 patients. Only one developed a new wall motion abnormality. The median estimated mass of myonecrosis was 2.0 g (range, 0.7 to 12.2 g), or 1.5% of left ventricular mass (range, 0.4% to 6.0%). Hyperenhancement persisted in 5 of the 6 who underwent a repeat MRI at 3 to 12 months. No control patient had hyperenhancement.

CONCLUSIONS

Contrast-enhanced MRI provides an anatomical correlate to biochemical evidence of procedure-related myocardial injury, despite the lack of ECG changes or wall motion abnormalities. Mild elevation of CK-MB after percutaneous coronary intervention is the result of discrete microinfarction.

Thrombotic thrombocytopenic purpura associated with clopidogrel

BACKGROUND

The antiplatelet drug clopidogrel is a new thienopyridine derivative whose mechanism of action and chemical structure are similar to those of ticlopidine. The estimated incidence of ticlopidine-associated thrombotic thrombocytopenic purpura is 1 per 1600 to 5000 patients treated, whereas no clopidogrel-associated cases were observed among 20,000 closely monitored patients treated in phase 3 clinical trials and cohort studies. Because of the association between ticlopidine use and thrombotic thrombocytopenic purpura and other adverse effects, clopidogrel has largely replaced ticlopidine in clinical practice. More than 3 million patients have received clopidogrel. We report the clinical and laboratory findings in 11 patients in whom thrombotic thrombocytopenic purpura developed during or soon after treatment with clopidogrel.

METHODS

The 11 patients were identified by active surveillance by the medical directors of blood banks (3 patients), hematologists (6), and the manufacturer of clopidogrel (2).

RESULTS

Ten of the 11 patients received clopidogrel for 14 days or less before the onset of thrombotic thrombocytopenic purpura. Although 10 of the 11 patients had a response to plasma exchange, 2 required 20 or more exchanges before clinical improvement occurred, and 2 had relapses while not receiving clopidogrel. One patient died despite undergoing plasma exchange soon after diagnosis.

CONCLUSIONS

Thrombotic thrombocytopenic purpura can occur after the initiation of clopidogrel therapy, often within the first two weeks of treatment. Physicians should be aware of the possibility of this syndrome when initiating clopidogrel treatment.

Randomized trial of contrast media utilization in high-risk PTCA: the COURT trial

BACKGROUND

Previous in vitro and in vivo studies have suggested an association between thrombus-related events and type of contrast media. Low osmolar contrast agents appear to improve the safety of diagnostic and coronary artery interventional procedures. However, no data are available on PTCA outcomes with an isosmolar contrast agent.

METHODS AND RESULTS

A multicenter prospective randomized double-blind trial was performed in 856 high-risk patients undergoing coronary artery intervention. The objective was to compare the isosmolar nonionic dimer iodixanol (n=405) with the low osmolar ionic agent ioxaglate (n=410). A composite variable of in-hospital major adverse clinical events (MACE) was the primary end point. A secondary objective was to evaluate major angiographic and procedural events during and after PTCA. The composite in-hospital primary end point was less frequent in those receiving iodixanol compared with those receiving ioxaglate (5.4% versus 9.5%, respectively; P=0.027). Core laboratory defined angiographic success was more frequent in patients receiving iodixanol (92.2% versus 85. 9% for ioxaglate, P=0.004). There was a trend toward lower total clinical events at 30 days in patients randomized to iodixanol (9.1% versus 13.2% for ioxaglate, P=0.07). Multivariate predictors of in-hospital MACE were use of ioxaglate (P=0.01) and treatment of a de novo lesion (P=0.03).

CONCLUSIONS

In this contemporary prospective multicenter trial of PTCA in the setting of acute coronary syndromes, there was a low incidence of in-hospital clinical events for both treatment groups. The cohort receiving the nonionic dimer iodixanol experienced a 45% reduction in in-hospital MACE when compared with the cohort receiving ioxaglate.

Exacerbation of radiocontrast nephrotoxicity by endothelin receptor antagonism

BACKGROUND

Endothelin is a potent vasoconstrictor that has been implicated in the pathogenesis of radiocontrast nephrotoxicity. Endothelin antagonists may reduce the renal hemodynamic abnormalities following radiocontrast administration.

METHODS

One hundred fifty-eight patients with chronic renal insufficiency [mean serum creatinine +/- SD = 2.7 +/- 1.0 mg/dL (242. 3 to +/- 92.8 micromol/L)] and undergoing cardiac angiography were randomized to receive either a mixed endothelin A and B receptor antagonist, SB 290670, or placebo. All patients received intravenous hydration with 0.45% saline before and after radiocontrast administration. Serum creatinine concentrations were measured at baseline, 24 hours, 48 hours, and 3 to 5 days after radiocontrast administration. The primary end point was the mean change in serum creatinine concentration from baseline at 48 hours; the secondary end point was the incidence of radiocontrast nephrotoxicity, defined as an increase in serum creatinine of > or =0.5 mg/dL (44 micromol/L) or > or = 25% from baseline within 48 hours of radiocontrast administration.

RESULTS

The mean increase in serum creatinine 48 hours after angiography was higher in the SB 209670 group [0.7 +/- 0. 7 mg/dL (63.5 +/- 58.6 micromol/L)] than in the placebo group [0.4 +/- 0.6 mg/dL (33.6 +/- 55.1 micromol/L), P = 0.002]. The incidence of radiocontrast nephrotoxicity was also higher in the SB 209670 group (56%) compared with placebo (29%, P = 0.002). This negative effect of SB 209670 was apparent in both diabetic and nondiabetic patients. Adverse effects, especially hypotension or decreased blood pressure, were more common in the SB 209670 group.

CONCLUSIONS

In patients with chronic renal insufficiency who were undergoing cardiac angiography, endothelin receptor antagonism with SB 209670 and intravenous hydration exacerbate radiocontrast nephrotoxicity compared with hydration alone.

Role of intracoronary ultrasound after high-pressure stent implantation

BACKGROUND

Poststent high-pressure balloon inflation has been shown to improve clinical outcomes. However, it is unknown whether intracoronary ultrasound (ICUS) provides additional clinical guidance after initial high-pressure balloon inflation is used during stent placement. Thus the purpose of this study was to determine if stent deployment techniques are improved with ICUS imaging despite an optimal angiographic result achieved with high-pressure balloon inflation.

METHODS AND RESULTS

Prospective data were collected on 96 consecutive patients in whom 151 stents were deployed. Stents and high-pressure balloons were angiographically sized 1:1 by visual estimation. High-pressure (> or =12 atm in all cases) balloon inflations were continued until angiographic completion (<10% residual stenosis), after which index ICUS imaging was performed. Stent apposition, symmetry, and lumen dimensions were evaluated. An optimal ICUS result was defined as full apposition of the stent, symmetry ratio > or =0.80, and acute gain > or =0.80 of the reference lumen area. If inadequate ICUS results were found, further dilations with higher pressures or larger balloons and subsequent stent reevaluation with ICUS were performed. Sixty-nine (46%) stents required additional balloon inflations. Of these stents, 35 (23%) had initial acute gains that were <80% of the reference lumen area. Forty-six (30%) stents were found to have unapposed struts and 24 (16%) had a symmetry ratio <0.80. In patients requiring additional inflations, minimum stent area increased from 7.6 +/- 2.2 mm(2) to 9.2 +/- 2.4 mm(2) (P <.0001). Similarly, complete stent apposition improved from 33% to 68% of total stents (P <.0001). After initial ICUS, higher-pressure dilations were performed in 40 patients, whereas larger balloons greater than or equal to ICUS reference vessel diameter were used in 33 patients. Follow-up was obtained in 95 (99%) patients. The overall major adverse cardiac event rate at 6 months was 9.3%, which consisted of 8 target vessel revascularizations and 1 abrupt closure requiring repeat intervention.

CONCLUSIONS

Even when poststent high-pressure balloon inflation achieves an optimal angiographic result, ICUS assists in optimizing acute gain, symmetry, and apposition of intracoronary stents in approximately 50% of patients. Moreover, ICUS guidance is associated with low rates for target vessel revascularization and major adverse cardiac events at 6-month follow-up.