Risk of Hematoma From Aspirin or Clopidogrel Owing to Lumbar Puncture

Lumbar Puncture in Thrombocytopenia: The Floor Is Not Firm

Objective Lumbar puncture (LP) is a diagnostic procedure that accesses the spinal subarachnoid space to measure the opening pressure of the cerebrospinal fluid (CSF) and obtain samples of CSF for analysis. Although commonly performed, LPs are associated with the risk of morbidity and mortality. In addition, thrombocytopenia is thought to increase the risk of LP complications, particularly spinal bleeds. This study compares rates of complications among patients who received LPs with and without thrombocytopenia in hopes of establishing more evidence-based platelet thresholds for an LP. Methods The TriNetX multi-institutional electronic health record database was used to perform a retrospective propensity score-matched analysis of clinical outcomes of two cohorts of patients who underwent LPs - those with thrombocytopenia (defined as a platelet level of 10,000-50,000 platelets {plts}/μL) and those without thrombocytopenia. The outcomes of interest were the new occurrence of subdural hematoma, epidural hematoma, subarachnoid hemorrhage, receipt of a blood patch, new onset of paralysis, and requirement of spinal decompression. Results The risk of developing a spinal bleed following an LP was 1.496% (42 of 2,808) for the cohort with thrombocytopenia versus 1.09% (31 of 2,843) for the cohort without thrombocytopenia. The risk difference, risk ratio, and odds ratio of patients from these two cohorts experiencing a spinal bleed following an LP were insignificant at 0.05. The risk of receiving a blood patch following an LP was 7.844% for those with thrombocytopenia compared to 1.421% for those without thrombocytopenia. The odds ratio of receiving a blood patch between the two cohorts was 5.906, significant to the 0.05 level (95% CI: 4.213-8.279). There was no significant difference in the cohorts' risk of developing paralysis or requiring spinal decompression following an LP. Conclusion In support of recent findings against conventional platelet count thresholds prior to LP, it was observed in the present study that the incidence of post-LP spinal bleeding in the 30 days after LP is not associated with platelet counts below the guideline threshold of 50,000 plts/μL. Patients with thrombocytopenia are also not significantly more likely to require spinal decompression or develop new onset paralysis. However, thrombocytopenia is associated with a significantly increased likelihood of receiving a blood patch following an LP.

Can we lower the platelet threshold of ≥ 50 × 109/L for performing a lumbar puncture safely in patients with hematological malignancies?

Lumbar punctures (LP) are routinely used to administer intrathecal chemotherapy for children and adults with hematologic malignancies. The current guidelines suggest a platelet threshold of ≥ 50 × 10⁹/L prior to LP for intrathecal chemotherapy (ITC). This can be challenging in patients with hematological malignancies who are thrombocytopenic. We conducted a retrospective chart review of 900 LPs for ITC and compared adverse events in patients with a platelet count of ≥ 50 × 10⁹/L and < 50 × 10⁹/L. Cohort 1 included 682 LPs (75.8%) with a pre-procedure platelet count ≥ 50 × 10⁹/L, and cohort 2 included 218 LPs (24.2%) with a pre-procedure platelet count < 50 × 10⁹/L. Cohort 2 was further subdivided into pre-procedure platelet counts of 41 × 10⁹/L-49 × 10⁹/L (n = 43), 31 × 10⁹/L-40 × 10⁹/L (n = 77), 21 × 10⁹/L-30 × 10⁹/L (n = 84), and 11 × 10⁹/L-20 × 10⁹/L (n = 14). Among 900 LP procedures, a pre-procedure platelet count < 50 × 10⁹/L did not demonstrate a higher rate of post-procedure adverse events (6.5% vs 6.8%, p = 0.8237). When cohort 2 was further stratified, the cohort with a pre-procedure platelet count of 21 × 10⁹/L-30 × 10⁹/L had the highest percentage of complications from LP (9.5%) and the highest rates of traumatic taps with observed LP RBC count > 200 (35.7%, p = 0.0015). The rate of red blood cells (RBC) in the CSF was significantly higher in the group with platelets < 50 × 10⁹/L with observed LP RBC count ≥ 200 (31.2% vs 20.5%, p = 0.0016), ≥ 500 (27.1% vs 14.6%, p < 0.0001), and ≥ 1000 (23% vs 11.6%, p < 0.0001). No instances of epidural hematomas were seen. We found no significant difference in bleeding complications between patients undergoing LPs for ITC with a platelet count above or below 50 × 10⁹/L.

Safety of lumbar puncture for people who are treated with ADP receptor antagonists

BACKGROUND

Current guidelines state that clopidogrel and other adenosine-diphosphate receptor antagonists (ADPra) should be stopped for at least 7 days before lumbar puncture (LP). This practice may delay the diagnosis of treatable neurological emergencies and may increase the risk of cardiovascular morbidity due to withholding antiplatelets. We aimed to summarize all cases under our care, in which LP was performed without discontinued ADPra.

METHODS

A retrospective case series study of all patients who underwent LP without interruption of ADPRa or with treatment interruption that was shorter than 7 days. Medical records were searched for documented complications. Traumatic tap was defined as cerebrospinal fluid red cell count ≥ 1000 cell/μL. Incidence of traumatic tap among people who underwent LP under ADPRa was compared to traumatic tap incidence in two control groups: LP under aspirin and LP without any anti-platelet.

RESULTS

159 patients underwent LP under ADPRa [Age: 68.4 ± 12.1, Female: 63 (40%), 81 (51%) were treated with both aspirin and ADPRa]. 116 procedures were carried out without any interruption of ADPRa. In the other 43, the median delay between treatment interruption and the procedure was 2 days (range: 1-6 days). Incidence of traumatic tap was 8/159 (5%), 9/159 (5.7%) and 4/160 (2.5%) among those who underwent LP under ADPRa, under aspirin and without any anti-platelet, respectively. [X²(2) = 2.13, P = 0.35)]. No patient developed spinal hematoma or any neurological deficit.

CONCLUSIONS

Lumbar puncture without discontinuation of ADP receptor antagonists seems safe. Similar case series may ultimately lead to guidelines change.

Lumbar Puncture: Indications, Challenges and Recent Advances

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Association of Lumbar Puncture With Spinal Hematoma in Patients With and Without Coagulopathy

IMPORTANCE

Coagulopathy may deter physicians from performing a lumbar puncture.

OBJECTIVE

To determine the risk of spinal hematoma after lumbar puncture in patients with and without coagulopathy.

DESIGN, SETTING, AND PARTICIPANTS

Danish nationwide, population-based cohort study using medical registries to identify persons who underwent lumbar puncture and had cerebrospinal fluid analysis (January 1, 2008-December 31, 2018; followed up through October 30, 2019). Coagulopathy was defined as platelets lower than 150 × 109/L, international normalized ratio (INR) greater than 1.4, or activated partial thromboplastin time (APTT) longer than 39 seconds.

EXPOSURES

Coagulopathy at the time of lumbar puncture.

MAIN OUTCOMES AND MEASURES

Thirty-day risk of spinal hematoma. Risks were provided as numbers and percentages with 95% CIs. Secondary analyses included risks of traumatic lumbar puncture (>300 × 106 erythrocytes/L after excluding patients diagnosed with subarachnoid hemorrhage). Adjusted hazard rate ratios (HRs) were computed using Cox regression models.

RESULTS

A total of 83 711 individual lumbar punctures were identified among 64 730 persons (51% female; median age, 43 years [interquartile range, 22-62 years]) at the time of the procedure. Thrombocytopenia was present in 7875 patients (9%), high INR levels in 1393 (2%), and prolonged APTT in 2604 (3%). Follow-up was complete for more than 99% of the study participants. Overall, spinal hematoma occurred within 30 days for 99 of 49 526 patients (0.20%; 95% CI, 0.16%-0.24%) without coagulopathy vs 24 of 10 371 patients (0.23%; 95% CI, 0.15%-0.34%) with coagulopathy. Independent risk factors for spinal hematoma were male sex (adjusted hazard ratio [HR], 1.72; 95% CI, 1.15-2.56), those aged 41 through 60 years (adjusted HR, 1.96; 95% CI, 1.01-3.81) and those aged 61 through 80 years (adjusted HR, 2.20; 95% CI, 1.12-4.33). Risks did not increase significantly according to overall severity of coagulopathy, in subgroup analyses of severity of coagulopathy by pediatric specialty or medical indication (infection, neurological condition, and hematological malignancy), nor by cumulative number of procedures. Traumatic lumbar punctures occurred more frequently among patients with INR levels of 1.5 to 2.0 (36.8%; 95% CI, 33.3%-40.4%), 2.1 to 2.5 (43.7%; 95% CI, 35.8%-51.8%), and 2.6 to 3.0 (41.9% 95% CI 30.5-53.9) vs those with normal INR (28.2%; 95% CI, 27.7%-28.75%). Traumatic spinal tap occurred more often in patients with an APTT of 40 to 60 seconds (26.3%; 95% CI, 24.2%-28.5%) vs those with normal APTT (21.3%; 95% CI, 20.6%-21.9%) yielding a risk difference of 5.1% (95% CI, 2.9%-7.2%).

CONCLUSIONS AND RELEVANCE

In this Danish cohort study, risk of spinal hematoma following lumbar puncture was 0.20% among patients without coagulopathy and 0.23% among those with coagulopathy. Although these findings may inform decision-making about lumbar puncture by describing rates in this sample, the observed rates may reflect bias due to physicians selecting relatively low-risk patients for lumbar puncture.