Symptomatic intracerebral hemorrhage following thrombolytic therapy for acute ischemic stroke: a review of the risk factors

A risk score to predict intracranial hemorrhage after recombinant tissue plasminogen activator for acute ischemic stroke

BACKGROUND

Ability to predict risk of postthrombolysis intracerebral hemorrhage (ICH) is currently limited.

METHODS

Using data from the Multicenter Recombinant Tissue Plasminogen Activator Stroke Survey Group, we developed a score to predict this risk. One point was assigned for the presence of each of 4 variables: age older than 60 years, baseline National Institutes of Health Stroke Scale score greater than 10, glucose greater than 8.325 mmol/L, and platelet count less than 150,000/mm(3).

RESULTS

Rate of any ICH increased with higher scores: 0 points, 2.6%; 1 point, 9.7%; 2 points, 15.1%; and greater than or equal to 3 points, 37.9%. The model had reasonable discriminatory capability (C-statistic 0.69). A similar pattern was seen with symptomatic and asymptomatic ICH separately, and with radiographically defined parenchymal hemorrhage.

CONCLUSION

A simple risk score may be useful for predicting postthrombolysis ICH.

Safety and Efficacy of Endovascular Thrombectomy in Patients With Abnormal Hemostasis

Background and Purpose— Patients with abnormal hemostasis are not considered candidates for thrombolysis. We analyzed the MERCI/Multi MERCI cohort as an attempt to establish the risks and benefits of thrombectomy in this patient population.

Methods— Two patient groups were identified: Group 1 (n=35): patients with INR >1.7 or PTT >45 seconds or platelet count <100 000/μL; Group 2 (n=270): patients with INR ≤1.7, PTT ≤45 seconds, and platelet count ≥100 000/μL. Clinical, radiographic, and revascularization outcomes were subsequently compared.

Results— In Group 1, 20 patients had INR >1.7 (mean: 2.4; range: 1.8 to 4.9), 11 had PTT >45 seconds (mean: 95; range: 46 to 190), and 6 had platelets <100 000/μL (mean: 63 400; range: 16 000 to 94 000). Two patients had both INR >1.7 and PTT >45 seconds. The two groups did not significantly differ in terms of age, gender, baseline NIHSS scores, intraarterial thrombolytic use/dosage, or occlusion site. Time-to-treatment was slightly earlier in Group 1. There was no significant difference in the rates of revascularization (TIMI 2 to 3: 60% versus 65%), mortality (40% versus 38%), or major symptomatic intracranial hemorrhage (SICH; 8.6% versus 8.5%). Group 2 had higher rates of good clinical outcomes (9% versus 35%; P =0.002). This was likely related to a lower prestroke health status in Group 1 patients. In Group 1, successful revascularization was associated with improved outcomes ( P =0.015) and lower mortality (24% versus 64%; P =0.033).

Conclusion— Patients with abnormal hemostasis who undergo thrombectomy do not appear to be at a higher risk for SICH but have lower rates of good outcomes. In this patient group, successful revascularization appears to be associated with improved clinical outcomes and lower mortality.

Liposomes for targeted delivery of antithrombotic drugs

BACKGROUND

Targeted delivery of antithrombotic (thrombolytic) drugs is expected to increase their efficacy and decrease side effects, especially in the case of thrombolytic enzymes. Liposomes, phospholipid nanosized bubbles with a bilayered membrane structure, have drawn a lot of interest as pharmaceutical carriers for drugs and genes. In particular, several attempts have been made to use liposomes as vehicles for antithrombotic agents.

OBJECTIVE

This review analyzes the available data on the application of liposomes, including liposomes targeted by specific ligands, for the delivery of antithrombotic/thrombolytic agents in order to increase their efficacy and decrease side effects.

METHODS

The papers published on the subject of liposomes loaded with antithrombotic agents, mainly over the last 10 - 15 years, will be discussed.

CONCLUSION

Liposomes loaded with various antithrombotic drugs, though they have been the subject of a significant number of experimental papers, can hardly be considered as real candidates for clinical application in the near future.

Predictors of hemorrhage following intra-arterial thrombolysis for acute ischemic stroke: the role of pial collateral formation

BACKGROUND AND PURPOSE

The extent of pial collateral formation during acute ischemic stroke has been shown to influence outcomes. This study examines whether angiographic assessment of pial collateral formation is predictive of hemorrhagic transformation following intra-arterial thrombolysis (IAT) for acute ischemic stroke.

MATERIALS AND METHODS

Rates of any hemorrhage and significant hemorrhage (>25 mL) were reviewed in 104 consecutive patients who underwent IAT following acute ischemic stroke. The influence of the anatomic extent of pial collateral formation on the rates of hemorrhage and significant hemorrhage relative to known predictors for hemorrhagic transformation (presenting systolic blood pressure, blood glucose level, platelet level, and National Institutes of Health Stroke Scale [NIHSS] score, history of diabetes, time to treatment, age, sex, occlusion site, and extent of reperfusion) was analyzed by using logistic regression models.

RESULTS

Rates of any hemorrhage and significant hemorrhage were 25.2% (26/104) and 9.7% (10/104), respectively. The rate of significant hemorrhage was 25.0% (8/32) in patients with poor pial collaterals and 2.78% (2/72) in those with good pial collaterals (P = .0004, Pearson correlation). The rate of any hemorrhage was also significantly higher in patients with poor pial collaterals (40.6% versus 18.1%; P = .0142, Pearson correlation). Logistic regression analyses revealed that pial collateral formation (odds ratio [OR] = 3.04), history of diabetes (OR = 4.83), platelets <200,000/microL (OR = 2.95), and time to treatment <3 hours (OR = 12.0) were statistically significant predictors of hemorrhage, whereas pial collateral formation (OR = 13.1) and platelets <200,000/microL (OR = 8.1) were statistically significant predictors of significant hemorrhage.

CONCLUSIONS

Poor pial collateral formation is associated with higher incidence and larger size of hemorrhage following IAT.

Does body weight influence the response to intravenous tissue plasminogen activator in stroke patients?

BACKGROUND

The recommended dose of IV tissue plasminogen activator (t-PA) for ischemic stroke patients weighing >100 kg (ISPW >100 kg) is fixed at 90 mg. Elevated levels of plasminogen activator inhibitor-1 (PAI-1) and impaired fibrinolysis have been reported in heavy patients, suggesting that ISPW >100 kg may require higher doses of t-PA. We hypothesized that ISPW >100 kg are less likely to benefit from IV t-PA compared to patients who weigh <or=100 kg and receive a weight-based dose.

METHODS

We queried the National Institute of Neurological Disorders and Stroke t-PA study database, and performed multivariate logistic regression analyses to analyze the effects of weight (>100 vs. <or=100 kg) and t-PA dose on functional outcomes at 3 months.

RESULTS

Six percent of the t-PA and 10% of the placebo cohorts had an actual body weight >100 kg. Weight >100 kg emerged as a predictor of worse outcome (OR = 5.76; p = 0.017) and neurological deterioration (OR = 3.4; p = 0.07) after t-PA. This negative impact of body weight on outcome was not seen among placebo-treated patients. We also found a trend for an association between lower doses of t-PA and unfavorable 3-month outcomes in t-PA-treated patients (OR = 1.9; p = 0.05).

CONCLUSIONS

ISPW >100 kg seem to derive less benefit from IV t-PA than their lighter counterparts. This may be partly attributed to the use of fixed non-weight-adjusted dosing in heavier patients. The mechanism(s) underlying this observation and its potential therapeutic implications require further investigations.

Characterization of ultrasound propagation through ex-vivo human temporal bone

Adjuvant therapies that lower the thrombolytic dose or increase its efficacy would represent a significant breakthrough in the treatment of patients with ischemic stroke. The objective of this study was to perform intracranial measurements of the acoustic pressure field generated by 0.12, 1.03 and 2.00-MHz ultrasound transducers to identify optimal ultrasound parameters that would maximize penetration and minimize aberration of the beam. To achieve this goal, in vitro experiments were conducted on five human skull specimens. In a water-filled tank, two unfocused transducers (0.12 and 1.03 MHz) and one focused transducer (2.00 MHz) were consecutively placed near the right temporal bone of each skull. A hydrophone, mounted on a micropositioning system, was moved to an estimated location of the middle cerebral artery (MCA) origin, and measurements of the surrounding acoustic pressure field were performed. For each measurement, the distance from the position of maximum acoustic pressure to the estimated origin of the MCA inside the skulls was quantified. The -3 dB depth-of-field and beamwidth in the skull were also investigated as a function of the three frequencies. Results show that the transducer alignment relative to the skull is a significant determinant of the detailed behavior of the acoustic field inside the skull. For optimal penetration, insonation normal to the temporal bone was needed. The shape of the 0.12-MHz intracranial beam was more distorted than those at 1.03 and 2.00 MHz because of the large aperture and beamwidth. However, lower ultrasound pressure reduction was observed at 0.12 MHz (22.5%). At 1.03 and 2.00 MHz, two skulls had an insufficient temporal bone window and attenuated the beam severely (up to 96.6% pressure reduction). For all frequencies, constructive and destructive interference patterns were seen near the contralateral skull wall at various elevations. The 0.12-MHz ultrasound beam depth-of-field was affected the most when passing through the temporal bone and showed a decrease in size of more than 55% on average. The speed of sound in the temporal bone of each skull was estimated at 1.03 MHz and demonstrated a large range (1752.1 to 3285.3 m/s). Attenuation coefficients at 1.03 and 2.00 MHz were also derived for each of the five skull specimens. This work provides needed information on ultrasound beam shapes inside the human skull, which is a necessary first step for the development of an optimal transcranial ultrasound-enhanced thrombolysis device.

Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke

BACKGROUND

Intravenous thrombolysis with alteplase is the only approved treatment for acute ischemic stroke, but its efficacy and safety when administered more than 3 hours after the onset of symptoms have not been established. We tested the efficacy and safety of alteplase administered between 3 and 4.5 hours after the onset of a stroke.

METHODS

After exclusion of patients with a brain hemorrhage or major infarction, as detected on a computed tomographic scan, we randomly assigned patients with acute ischemic stroke in a 1:1 double-blind fashion to receive treatment with intravenous alteplase (0.9 mg per kilogram of body weight) or placebo. The primary end point was disability at 90 days, dichotomized as a favorable outcome (a score of 0 or 1 on the modified Rankin scale, which has a range of 0 to 6, with 0 indicating no symptoms at all and 6 indicating death) or an unfavorable outcome (a score of 2 to 6 on the modified Rankin scale). The secondary end point was a global outcome analysis of four neurologic and disability scores combined. Safety end points included death, symptomatic intracranial hemorrhage, and other serious adverse events.

RESULTS

We enrolled a total of 821 patients in the study and randomly assigned 418 to the alteplase group and 403 to the placebo group. The median time for the administration of alteplase was 3 hours 59 minutes. More patients had a favorable outcome with alteplase than with placebo (52.4% vs. 45.2%; odds ratio, 1.34; 95% confidence interval [CI], 1.02 to 1.76; P=0.04). In the global analysis, the outcome was also improved with alteplase as compared with placebo (odds ratio, 1.28; 95% CI, 1.00 to 1.65; P<0.05). The incidence of intracranial hemorrhage was higher with alteplase than with placebo (for any intracranial hemorrhage, 27.0% vs. 17.6%; P=0.001; for symptomatic intracranial hemorrhage, 2.4% vs. 0.2%; P=0.008). Mortality did not differ significantly between the alteplase and placebo groups (7.7% and 8.4%, respectively; P=0.68). There was no significant difference in the rate of other serious adverse events.

CONCLUSIONS

As compared with placebo, intravenous alteplase administered between 3 and 4.5 hours after the onset of symptoms significantly improved clinical outcomes in patients with acute ischemic stroke; alteplase was more frequently associated with symptomatic intracranial hemorrhage. (ClinicalTrials.gov number, NCT00153036.)

Accelerated dosing frequency of a pulmonary formulation of tissue plasminogen activator is well-tolerated in mice

1. Tissue plasminogen activator (tPA) has both fibrinolytic and anti-inflammatory activity. These properties may be useful in treating inflammatory lung diseases, such as acute respiratory distress syndrome (ARDS). 2. We have previously demonstrated the feasibility of targeted pulmonary delivery of tPA. As part of our research to develop a clinically viable pulmonary formulation of tPA, we assessed the tolerability and incidence of haemorrhage associated with the administration of a pulmonary formulation of mouse tPA (pf-mtPA). 3. Intratracheal doses of nebulized pf-mtPA or sterile saline were administered with increasing frequency to male and female B6C3F1 mice. After dosing, the mice entered a recovery period, after which they were killed and their lungs were lavaged and harvested. Post-mortem gross necropsy was performed and all major organs were assessed histologically for haemorrhage. The bronchoalveolar lavage fluid was assessed for markers of lung injury. 4. Mouse tPA that was formulated to mimic a previously characterized human pf-tPA was well tolerated when given intratracheally with increasing dosing frequency. The administration of pf-mtPA did not result in any detectable haemorrhagic-related events or signs of lung injury. 5. The results of the present longitudinal study demonstrate that a maximally feasible dose of pf-mtPA (3 mg/kg) can be given frequently over a short period of time (12 h) without haemorrhagic complications. Although these data were generated in a healthy mouse model, they provide support for the continued evaluation of pf-tPA for the treatment of pulmonary diseases, such as ARDS.

Emergency surgery for complicated colorectal cancer. A two-decade trend analysis

BACKGROUND/AIMS

Emergency procedures for colorectal cancer have worse outcomes than elective resections. Temporal trends in emergency surgery are analyzed by comparing two decade-related series of colorectal cancer patients.

METHODS

The clinical data of 985 patients undergoing colorectal cancer surgery were collected during two decades (1975-1984 and 1995-2004). Rates of emergency surgery, operative mortality, 5-year cancer-related and overall survival were compared retrospectively.

RESULTS

The rate of emergency surgery decreased from 81 out of 513 cases (16%) during 1975-1984 to 41 out of 471 cases (9%) during 1995-2004 (p = 0.005). Over the same time, the rate of curative resections in emergency increased from 46% (37/81 cases) to 76% (31/41 cases) (p < 0.001), while patient and tumor characteristics remained similar. Operative mortality after emergency procedures decreased from 14% (11 deaths) to 5% (2 deaths) and cancer-related survival increased from 21 to 42% (p = 0.03). However, when excluding palliative procedures, survival after emergency surgery increased from 52 to 58%, while after elective treatment it increased from 56 to 78% (p < 0.001).

CONCLUSIONS

Frequency and operative mortality of emergency colorectal cancer surgery decreased substantially from 1975-1984 to 1995-2004. No significant improvement in long-term survival was observed when curative emergency resections only were considered. Further efforts are needed to reverse the diverging trend of long-term outcomes between emergency and elective curative procedures.