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"Cancer patients had longer PICC durations and higher PICC thrombosis rates than those without (7% vs 0.7%)" Yuen et al (2021).

PICC thrombosis risk score


Background: Peripherally inserted central catheter (PICC) thrombosis is common.

Objectives: To explore the prevalence of symptomatic PICC thrombosis and pulmonary embolism/deep vein thrombosis (PE/DVT) in cancer and non-cancer cohorts. In active cancer we assessed the Khorana and Michigan Risk Score (KRS, MRS) for predicting PICC thrombosis and modifications to improve discriminative accuracy.

Methods: We reviewed consecutive cancer patients receiving chemotherapy through a PICC inserted April 2017 to July 2018. For each case, we identified a contemporaneous non-control.

Results: Among 147 cancer patients, median age 64 years, PICC duration 70 days (range, 2-452), 7% developed PICC thrombosis (95%CI 3.6-12.2) and 4%(95%CI 2-9) PE/DVT. Among 147 controls, median age 68 years, PICC duration 18.3 days (range, 0.5-210), 0.7%(95%CI 0-4) developed PICC thrombosis and 2%(95%CI 0.4-6) PE/DVT. In our cancer cohort, no KRS<1 patients developed PICC thrombosis (95%CI 0-11) compared to 9% (95%CI 5-16) in KRS≥1, p=0.12. PICC thrombosis occurred in 4.7% (95%CI 1.5-11.7) MRS3 compared to 10.9% (95%CI 4.1-22.2) MRS>3, p=0.32. The addition of thrombocytosis, a variable from KRS, to MRS (modified MRS, mMRS) improved discriminative value for PICC thrombosis (c-statistic MRS 0.63 [95%CI 0.44-0.82], mMRS 0.72 [95%CI 0.58-0.85]). PICC thrombosis occurred in 1.4% (95%CI 0-8.3) mMRS3 and 11.8% (95%CI 6.1-21.2) mMRS>3, p=0.02. More patients were categorized as low risk using mMRS3 (47%) than KRS<1 (22%).

Conclusion: Cancer patients had longer PICC durations and higher PICC thrombosis rates than those without (7% vs 0.7%). mMRS more accurately classified low PICC thrombosis risk than KRS<1(47% versus 22%). Prospective validation of mMRS is warranted.


Yuen HLA, Zhao J, Tran H, Chunilal S. Development of a risk score to predict peripherally inserted central catheter thrombosis in active cancer. Intern Med J. 2021 Oct 6. doi: 10.1111/imj.15557. Epub ahead of print. PMID: 34613657.