Bruce E. Lewis

Failure of early heparin cessation as treatment for heparin-induced thrombocytopenia.

PURPOSE The complications of heparin-induced thrombocytopenia include thrombosis and death. The purpose of the study was to determine whether early heparin cessation can prevent these outcomes. SUBJECTS AND METHODS We performed a retrospective analysis of consecutive patients with heparin-induced thrombocytopenia diagnosed by platelet aggregometry. Demographic, clinical, and laboratory findings were compared in patients by whether heparin treatment was stopped early (< or = 48 hours) or late (>48 hours) after the onset of thrombocytopenia, as well as between patients with and without thrombosis. Thrombocytopenia was defined as a 50% decline in baseline platelet counts or an absolute platelet count < 100,000/mm3. RESULTS Of the 113 patients, 38% developed thrombosis and 27% died. One-half of patients had thrombosis diagnosed >24 hours after heparin cessation. No difference in thrombosis or mortality was found in the 40 patients with early heparin cessation [mean (+/-SD) time of cessation 0.7 +/- 0.6 days] compared with the 73 patients with late heparin cessation (5 +/- 3 days). Thrombosis >24 hours after heparin cessation occurred in 61% of the patients in the early group and in 40% of the late group (P = 0.17). In a multivariate analysis, only a lower nadir of the platelet count (percent of baseline) was associated with thrombosis. Neither thrombosis nor the time to heparin cessation were associated with mortality. CONCLUSIONS Early heparin cessation was not effective in reducing morbid events in patients with heparin-induced thrombocytopenia. Treatment strategies other than heparin cessation alone should be considered in patients with this condition.

Argatroban anticoagulation during percutaneous coronary intervention in patients with heparin‐induced thrombocytopenia

Heparin‐induced thrombocytopenia (HIT) is an immune‐mediated syndrome associated with thrombosis. Alternative anticoagulation to heparin is needed for HIT patients during percutaneous coronary intervention (PCI). We evaluated argatroban, a direct thrombin inhibitor, for anticoagulation in this setting. Ninety‐one HIT patients underwent 112 PCIs while on intravenous argatroban (25 μg/kg/min [350 μg/kg initial bolus], adjusted to achieve an activated clotting time of 300–450 sec). Primary efficacy endpoints were subjective assessments of the satisfactory outcome of the procedure and adequate anticoagulation during PCI. Among patients undergoing initial PCIs with argatroban (n = 91), 94.5% had a satisfactory outcome of the procedure and 97.8% achieved adequate anticoagulation. Death (zero patients), myocardial infarction (four patients), or revascularization (four patients) at 24 hr after PCI occurred in seven (7.7%) patients overall. One patient (1.1%) experienced periprocedural major bleeding. For patients who had subsequent hospitalizations (mean separation of 150 days) for repeat PCI using argatroban anticoagulation (n = 21), there were no unsatisfactory outcomes. Overall, outcomes were comparable with those historically reported for heparin. Argatroban therefore is a reasonable anticoagulant option in this setting, where current options are limited. Cathet Cardiovasc Intervent 2002;57:177–184.

Acute endothelin A receptor blockade causes selective pulmonary vasodilation in patients with chronic heart failure

BACKGROUND Elevated plasma endothelin-1 (ET-1) levels in patients with chronic heart failure correlate with pulmonary artery pressures and pulmonary vascular resistance. ET(A) receptors on vascular smooth muscle cells mediate pulmonary vascular contraction and hypertrophy. We determined the acute hemodynamic effects of sitaxsentan, a selective ET(A) receptor antagonist, in patients with chronic stable heart failure receiving conventional therapy. METHODS AND RESULTS This multicenter, double-blind, placebo-controlled trial enrolled 48 patients with chronic New York Heart Association functional class III or IV heart failure (mean left ventricular ejection fraction 21+/-1%) treated with ACE inhibitors and diuretics. Patients with a baseline pulmonary capillary wedge pressure >/=15 mm Hg and a cardiac index </=2.5 L. min(-1). m(-2) were randomized to 1 of 3 doses (1.5, 3.0, or 6.0 mg/kg) of sitaxsentan or placebo as an intravenous infusion over 15 minutes. Hemodynamic responses were assessed by catheterization of the right side of the heart for 6 hours. Sitaxsentan decreased pulmonary artery systolic pressure, pulmonary vascular resistance, mean pulmonary artery pressure, and right atrial pressure (P</=0.001, 0.003, 0.017, and 0.031, respectively) but had no effect on heart rate, mean arterial pressure, pulmonary capillary wedge pressure, cardiac index, or systemic vascular resistance. Plasma ET-1 levels were elevated at baseline and decreased with sitaxsentan. CONCLUSIONS In patients with moderate to severe heart failure receiving conventional therapy, acute ET(A) receptor blockade caused selective pulmonary vasodilation associated with a reduction in plasma ET-1. Sitaxsentan may be of value in the treatment of patients with pulmonary hypertension secondary to chronic heart failure.

Use of vascular sealing devices (VasoSeal and Perclose) versus assisted manual compression (Femostop) in transcatheter coronary interventions requiring Abciximab (ReoPro)

Transcatheter coronary interventions requiring abciximab (ReoPro) are associated with vascular access site complications. Several devices have been developed to aid in the closure of the femoral arteriotomy, including collagen plug devices (VasoSeal, Angio‐Seal), percutaneous suture closure (Perclose), and aids to manual compression (Femostop). In 185 patients who received abciximab plus aspirin and heparin for transcatheter coronary interventions, we compared femoral arteriotomy closure by three different methods: VasoSeal, Perclose, and Femostop. A composite endpoint of late complications defined as an access site‐related bleed or hematoma that required blood transfusion or an extended hospital stay, pseudoaneurysm, arteriovenous fistula, arterial or venous thrombosis was compared. VasoSeal was initially successful in 41/52 patients (78.8%). The 11 patients who failed to have adequate hemostasis with VasoSeal required manual compression aided by Femostop, but had no late complications. There was one access site infection and one fatal retroperitoneal hematoma unrelated to the vascular access site (surgically explored). There were no late complications. Perclose was successful in 48/56 patients (85.7%). One Perclose failure required surgical repair for an extensive arteriotomy. The other Perclose failure required manual compression aided by Femostop, but had no late complications. There were no access site infections requiring intravenous antibiotics. There was one retroperitoneal bleed that extended the patients hospital stay and for which a blood transfusion was required. Femostop was successful in 77/77 patients (100%). There were no infections. Late complications occurred in four patients. These included three episodes of bleeding or hematomas requiring blood transfusion, and one pseudoaneurysm. Conclusion: In patients receiving abciximab in addition to aspirin and heparin, VasoSeal and Perclose are at least as safe as Femostop when used to achieve homeostasis after sheath removal. VasoSeal and Perclose have a significantly lower initial rate of successful hemostasis than Femostop. The numbers of late complications between the VasoSeal, Perclose, and Femostop groups were not significantly different. In those patients in whom VasoSeal or Perclose failed, no late complications occurred. Access site infections were no different between VasoSeal, Perclose, and Femostop. Cathet. Cardiovasc. Intervent. 47:143–147, 1999.

Argatroban therapy does not generate antibodies that alter its anticoagulant activity in patients with heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is an immune-mediated syndrome that can lead to limb- and life-threatening thrombosis. Argatroban, a small synthetic molecule (Argatroban; GlaxoSmithKline, Philadelphia, PA), and lepirudin, a protein of non-human origin (Refludan; Aventis, Bridgewater, NJ), are direct thrombin inhibitors that have been used successfully for anticoagulant therapy in HIT patients. It has been reported that between 44-74% of lepirudin-treated HIT patients develop drug-specific antibodies that either enhance or suppress the anticoagulant activity of lepirudin. By contrast, there have been no reported patient experiences suggestive of unexpected loss or enhancement of argatrobans anticoagulant effect in clinical trials, including those in HIT patients, or in postmarketing safety surveillance of over 4,800 patients treated in Japan. To confirm the lack of antibodies in argatroban-treated patients with HIT, we examined plasma for anticoagulant-altering activity and reviewed dosing patterns of re-exposed patients. Paired, pre-therapy and post-therapy (> or =7 days) plasma pools exhibited comparable in vitro anticoagulant responses (aPTT and antithrombin activity) to argatroban supplementation. Argatroban at 5 microg/mL similarly prolonged aPTTs of normal plasma pretreated with IgG isolated from pre-therapy versus post-therapy plasma (P>0.6). In trials, mean argatroban doses during initial therapy versus re-exposure were not different among individuals anticoagulated for the treatment or prophylaxis of thrombosis (P=0.60) or during percutaneous coronary interventions (P=0.79), with no discernable pattern of suppression or enhancement of argatroban anticoagulation. Consistent with the lack of reported patient experiences suggestive of unexpected loss or enhancement of argatrobans anticoagulant effect across clinical trials and post-marketing safety surveillance, these data support the lack of anti-argatroban antibodies that affect drug activity in argatroban-treated HIT patients.

Transitioning from Argatroban to Warfarin Therapy in Patients with Heparin-induced Thrombocytopenia

Argatroban, a direct thrombin inhibitor used for thromboprophylaxis or treatment in heparin-induced thrombocytopenia (HIT), is routinely monitored using the activated partial thromboplastin time (aPTT) yet also prolongs the international normalized ratio (INR). Peritransitional INRs, aPTTs, anticoagulant dosing patterns, and outcomes were evaluated in 165 HIT patients who were transitioned, without guidelines, from argatroban to warfarin therapy. Argatroban (median doses: 1.5-2.0 mcg/kg/min) and warfarin (median dose: 5 mg initially with 3.8 mg/day thereafter) overlapped a median 4 days. Median (5-95th percentile) aPTTs (in seconds) and INRs, respectively, were 59.8 (38.8-82.9) and 3.2 (1.7-7.0) during argatroban monotherapy, 68.6 (44.5-104) and 5.3 (2.4-16) maximally during cotherapy, 59.9 (38.7-92.2) and 4.0 (2.2-11.6) immediately before argatroban cessation during cotherapy, and 36.0 (25.6-60.2) and 2.3 (1.3-7.3) within a median 10-12 hours after argatroban cessation. Major bleeding occurred in 1 (0.6%) patient pretransitionally and no patient during or after cotherapy. Eighteen (10.9%) patients experienced 19 peritransitional adverse outcomes (one death, two amputations, 16 new thromboses); these patients had more severe HIT than event-free patients (median baseline platelet count, 39 vs. 83 × 109/L). Of 108 patients with post-transitional INR data, 43 achieved a therapeutic INR (prospectively defined as 1.9-3.5), 34 were subtherapeutic, and 31 were supratherapeutic, with no across-group trend in new thrombosis. Hence in the absence of guidelines, physicians transfer patients from argatroban to warfarin therapy with acceptably low complication rates in HIT, without systematically over- or under-dosing warfarin. Furthermore, INRs greater than 5 commonly occur in HIT patients during argatroban monotherapy and argatroban/warfarin cotherapy, without major bleeding.

Argatroban anticoagulation in conjunction with glycoprotein IIb/IIIa inhibition in patients undergoing percutaneous coronary intervention: An open-label, nonrandomized pilot study

Background: Argatroban, a direct thrombin inhibitor, blocks clot-bound thrombin more effectively than does heparin. This multicenter, prospective pilot study evaluated the efficacy and safety of argatroban in combination with glycoprotein IIb/IIIa inhibition in patients undergoing percutaneous coronary intervention.Methods: Patients (N = 152) received argatroban as a 250- or 300-μg/kg bolus, followed by a 15-μg/kg/min infusion during percutaneous coronary intervention. An additional 150-μg/kg bolus was administered if activated clotting times 5–15 min after initiating argatroban were <275 s. Abciximab (N = 150) or double-bolus eptifibatide (N = 2) was administered simultaneously.Results: Median activated clotting times at the beginning and end of the procedure were approximately 300 s. The primary efficacy endpoint—a composite of death, myocardial infarction, or urgent revascularization at 30 days—occurred in 4 (2.6%) patients (no death, 4 myocardial infarctions, and 2 revascularizations). Two (1.3%) patients had major bleeding by the Thrombolysis in Myocardial Infarction criteria (1 retroperitoneal, 1 groin hematoma).Conclusions: Argatroban in combination with glycoprotein IIb/IIIa inhibition appears to provide adequate anticoagulation and be well tolerated with an acceptable bleeding risk for patients undergoing percutaneous coronary intervention. Additional studies are warranted.

Acute procedural results in the treatment of 30 coronary artery bifurcation lesions with a double-wire atherectomy technique for side-branch protection

Percutaneous treatment of bifurcation lesions has been consistently shown to be associated with lower acute success rates, higher initial complication rates, and an increased rate of restenosis when compared with findings in nonbifurcation lesions. Recent analysis of data from a CAVEAT subgroup suggests that directional atherectomy of bifurcation lesions can improve initial success rates and lower restenosis rates but at the cost of high complication rates. Reports from several angioplasty series document improved success rates and lower complication rates with the use of a two-wire technique to protect side branches when treating bifurcation lesions. Our experience with a two-wire atherectomy technique that uses a nitinol wire to protect important side branches is presented.

Long-term clinical outcomes of real-world experience using sirolimus-eluting stents in saphenous vein graft disease

Objective: To evaluate the long‐term clinical outcomes of patients undergoing percutaneous coronary intervention for saphenous vein graft (SVG) disease. Specifically, we compared clinical endpoints of patients who received sirolimus‐eluting stents (SES) versus bare‐metal stents (BMS) for SVG disease. Background: A recent small randomized‐controlled trial (RCT) reported increased mortality with the use of SES in SVG disease. Methods: We retrospectively identified patients who underwent SES placement for a SVG lesion(s) at our institutions over a 4‐year period. The procedural and medical records were reviewed to identify predetermined clinical outcomes. Results: 318 patients who underwent SES placement for a SVG lesion were identified. 7 patients were lost to follow‐up. 141/311 patients (45%) received SES, while 170/311 (55%) received BMS. At a mean follow‐up of 34 months, there was a reduction in target lesion revascularization (TLR) (7% vs. 14%, P = 0.07) without an increased risk of mortality (6% vs. 12%, P = 0.06) in patients who received SES compared to patients who received BMS. When compared to the recent RCTs SES patients at long‐term follow‐up, our SES patients had significantly less mortality; rates of myocardial infarction, TLR, target vessel revascularization, and major adverse cardiac events; and were more likely to be taking dual antiplatelet and statin medications. Conclusion: Our results support that SES used in SVG lesions result in a reduction in TLR without an increased risk of mortality, and therefore may be an equally safe and feasible technique for revascularization with excellent long‐term clinical outcomes. These patients may benefit from prolonged dual antiplatelet and statin medication regimens.

Antithrombin Agents: The New Class of Anticoagulant and Antithrombotic Drugs

The plasma levels of soluble thrombomodulin (TM) were measured in 44 patients with chronic myeloprolif erative disorder, 15 with polycythemia vera (PV), 29 with es sential thrombocythemia (ET), and a group of 62 matched healthy controls. The younger patients had significantly lower TM levels (mean: 15.6 ± 4.8 ng/mL) than the older patients (mean: 28.6 ± 8.2 ng/mL, p < .001). Moreover, a significant negative correlation between platelet counts and plasma TM levels in healthy persons was noted (r = 0.317, p < .05). The only significant difference we found in plasma TM levels be tween patients and controls or among patients was between the young patients with ET (mean: 29.0 ± 19.2 ng/mL) and young healthy controls (mean: 15.6 ± 4.8 ng/mL). It is possible that younger ET patients with more active platelets are more sus ceptible to earlier vascular damage. The lack of any significant difference compared with the older patient population supports this hypothesis. Key Words: Thrombomodulin—Essential thrombocythemia—Polycythemia vera.