Marc Carrier, MD
@marccarriermd.bsky.social
Hematologist 🩸| Blood clot lover | Division Head @Ottawa Hospital | Senior Scientist @OHRI | Professor of Medicine at University of Ottawa
🩸 Key takeaways from 2025 CanVECTOR meeting
Even with standard LMWH thromboprophylaxis, fewer than half of ICU patients reach target anti-Xa levels.
🔹 Sub-prophylactic anti-Xa levels → ~3× higher risk of VTE
Time to reconsider “standard dosing” in the ICU.
Even with standard LMWH thromboprophylaxis, fewer than half of ICU patients reach target anti-Xa levels.
🔹 Sub-prophylactic anti-Xa levels → ~3× higher risk of VTE
Time to reconsider “standard dosing” in the ICU.
October 24, 2025 at 2:58 PM
🩸 Key takeaways from 2025 CanVECTOR meeting
Even with standard LMWH thromboprophylaxis, fewer than half of ICU patients reach target anti-Xa levels.
🔹 Sub-prophylactic anti-Xa levels → ~3× higher risk of VTE
Time to reconsider “standard dosing” in the ICU.
Even with standard LMWH thromboprophylaxis, fewer than half of ICU patients reach target anti-Xa levels.
🔹 Sub-prophylactic anti-Xa levels → ~3× higher risk of VTE
Time to reconsider “standard dosing” in the ICU.
Are you the person everyone calls when anticoagulation gets complicated?
Then you’ll fit right in at the Thrombosis Canada Annual Conference!
Join colleagues from across the country to connect, learn, and debate complex #VTE and #Anticoagulation cases during our Morning Report.
thrombosiscanada.ca
Then you’ll fit right in at the Thrombosis Canada Annual Conference!
Join colleagues from across the country to connect, learn, and debate complex #VTE and #Anticoagulation cases during our Morning Report.
thrombosiscanada.ca
October 23, 2025 at 11:36 AM
Are you the person everyone calls when anticoagulation gets complicated?
Then you’ll fit right in at the Thrombosis Canada Annual Conference!
Join colleagues from across the country to connect, learn, and debate complex #VTE and #Anticoagulation cases during our Morning Report.
thrombosiscanada.ca
Then you’ll fit right in at the Thrombosis Canada Annual Conference!
Join colleagues from across the country to connect, learn, and debate complex #VTE and #Anticoagulation cases during our Morning Report.
thrombosiscanada.ca
Reposted by Marc Carrier, MD
Drs. Kevin Durr, Alexandre Tran & Marc Carrier's @marccarriermd.bsky.social study on personalized risk stratification and reduction of venous thromboembolism among critically ill patients: www.psifoundation.org/funded-resea... #WorldThrombosisDay #ThrombosisResearch @ottawahospital.on.ca
Funded Research - PSI Foundation
List of projects funded by PSI Foundation.
www.psifoundation.org
October 14, 2025 at 5:07 PM
Drs. Kevin Durr, Alexandre Tran & Marc Carrier's @marccarriermd.bsky.social study on personalized risk stratification and reduction of venous thromboembolism among critically ill patients: www.psifoundation.org/funded-resea... #WorldThrombosisDay #ThrombosisResearch @ottawahospital.on.ca
#AQUATICtrial In chronic coronary syndrome pts at high 🫀atherothrombotic risk on long-term oral anticoagulation (OAC), adding ASA
↑ CV events (HR 1.53), death (HR 1.72) & major bleeding (HR 3.35) without benefit.
OAC alone safer. Published in @nejm.org www.nejm.org/doi/full/10....
↑ CV events (HR 1.53), death (HR 1.72) & major bleeding (HR 3.35) without benefit.
OAC alone safer. Published in @nejm.org www.nejm.org/doi/full/10....
Aspirin in Patients with Chronic Coronary Syndrome Receiving Oral Anticoagulation | NEJM
The appropriate antithrombotic regimen for patients with chronic coronary syndrome
who are at high atherothrombotic risk and receiving long-term oral anticoagulation
remains unknown. We conducted a...
www.nejm.org
August 31, 2025 at 8:44 PM
#AQUATICtrial In chronic coronary syndrome pts at high 🫀atherothrombotic risk on long-term oral anticoagulation (OAC), adding ASA
↑ CV events (HR 1.53), death (HR 1.72) & major bleeding (HR 3.35) without benefit.
OAC alone safer. Published in @nejm.org www.nejm.org/doi/full/10....
↑ CV events (HR 1.53), death (HR 1.72) & major bleeding (HR 3.35) without benefit.
OAC alone safer. Published in @nejm.org www.nejm.org/doi/full/10....
📢 New in @NEJM: In patients with provoked VTE + enduring risks, 12 mo of low-dose apixaban cut recurrent VTE by ~90% (1.3% vs 10.0%) 🩸 Major bleeding rare (1 pt).
👉 www.nejm.org/doi/full/10....
👉 www.nejm.org/doi/full/10....
Apixaban for Extended Treatment of Provoked Venous Thromboembolism | NEJM
The appropriate duration of anticoagulation for venous thromboembolism (VTE) in patients
who have a transient provoking factor (e.g., surgery, trauma, or immobility) and concomitant
enduring risk f...
www.nejm.org
August 31, 2025 at 2:25 AM
📢 New in @NEJM: In patients with provoked VTE + enduring risks, 12 mo of low-dose apixaban cut recurrent VTE by ~90% (1.3% vs 10.0%) 🩸 Major bleeding rare (1 pt).
👉 www.nejm.org/doi/full/10....
👉 www.nejm.org/doi/full/10....
Radiotherapy may independently increase the risk of venous thromboembolism. 🩸⚡
This review in @rpth.bsky.social unpacks mechanisms, diagnostic challenges, and why thromboprophylaxis should be tailored rather than routine.
👉 doi.org/10.1016/j.rp...
#Thrombosis #Oncology #CancerResearch
This review in @rpth.bsky.social unpacks mechanisms, diagnostic challenges, and why thromboprophylaxis should be tailored rather than routine.
👉 doi.org/10.1016/j.rp...
#Thrombosis #Oncology #CancerResearch
August 17, 2025 at 8:06 PM
Radiotherapy may independently increase the risk of venous thromboembolism. 🩸⚡
This review in @rpth.bsky.social unpacks mechanisms, diagnostic challenges, and why thromboprophylaxis should be tailored rather than routine.
👉 doi.org/10.1016/j.rp...
#Thrombosis #Oncology #CancerResearch
This review in @rpth.bsky.social unpacks mechanisms, diagnostic challenges, and why thromboprophylaxis should be tailored rather than routine.
👉 doi.org/10.1016/j.rp...
#Thrombosis #Oncology #CancerResearch
A new @thrombosiscan.bsky.social survey found that >50% of Canadian cancer patients have little or no awareness of cancer-associated thrombosis (CAT) — a major cause of death in cancer.
📊 Only 27% recalled being educated on CAT risks, yet most want more info!
doi.org/10.1055/a-26...
📊 Only 27% recalled being educated on CAT risks, yet most want more info!
doi.org/10.1055/a-26...
August 14, 2025 at 7:59 PM
A new @thrombosiscan.bsky.social survey found that >50% of Canadian cancer patients have little or no awareness of cancer-associated thrombosis (CAT) — a major cause of death in cancer.
📊 Only 27% recalled being educated on CAT risks, yet most want more info!
doi.org/10.1055/a-26...
📊 Only 27% recalled being educated on CAT risks, yet most want more info!
doi.org/10.1055/a-26...
☀️ A morning walk, fresh air, and great company – the perfect way to kick off a busy day at #ASHCRTI! 🏃♀️💬
Nothing like connecting with colleagues and faculty before diving into a full day of learning. Thanks to everyone who joined us this morning! 🙌
@ash.hematology.org
Nothing like connecting with colleagues and faculty before diving into a full day of learning. Thanks to everyone who joined us this morning! 🙌
@ash.hematology.org
August 6, 2025 at 6:19 PM
☀️ A morning walk, fresh air, and great company – the perfect way to kick off a busy day at #ASHCRTI! 🏃♀️💬
Nothing like connecting with colleagues and faculty before diving into a full day of learning. Thanks to everyone who joined us this morning! 🙌
@ash.hematology.org
Nothing like connecting with colleagues and faculty before diving into a full day of learning. Thanks to everyone who joined us this morning! 🙌
@ash.hematology.org
🧵1/
Diagnosing recurrent venous thromboembolism (VTE) is hard.
The international, multicenter PREDICTORS study (n=723) shows that while clinical decision rules (CDRs) still help stratify risk, they’re less effective at ruling out recurrence without imaging.
🩺📉
Diagnosing recurrent venous thromboembolism (VTE) is hard.
The international, multicenter PREDICTORS study (n=723) shows that while clinical decision rules (CDRs) still help stratify risk, they’re less effective at ruling out recurrence without imaging.
🩺📉
July 23, 2025 at 3:22 PM
🧵1/
Diagnosing recurrent venous thromboembolism (VTE) is hard.
The international, multicenter PREDICTORS study (n=723) shows that while clinical decision rules (CDRs) still help stratify risk, they’re less effective at ruling out recurrence without imaging.
🩺📉
Diagnosing recurrent venous thromboembolism (VTE) is hard.
The international, multicenter PREDICTORS study (n=723) shows that while clinical decision rules (CDRs) still help stratify risk, they’re less effective at ruling out recurrence without imaging.
🩺📉
Reposted by Marc Carrier, MD
🆕 A new study protocol START aims to investigate the best strategies to reduce risk of thrombosis and thrombocytopenia in cancer patients. @marccarriermd.bsky.social
👉 Click here to read more about the study design and goals! www.rpthjournal.org/article/S247...
👉 Click here to read more about the study design and goals! www.rpthjournal.org/article/S247...
July 16, 2025 at 12:02 PM
🆕 A new study protocol START aims to investigate the best strategies to reduce risk of thrombosis and thrombocytopenia in cancer patients. @marccarriermd.bsky.social
👉 Click here to read more about the study design and goals! www.rpthjournal.org/article/S247...
👉 Click here to read more about the study design and goals! www.rpthjournal.org/article/S247...
Reposted by Marc Carrier, MD
Marc Rodger highlighting the #Highlow study and providing guidance on how to implement the results 👌🏼
June 25, 2025 at 1:52 PM
Implementation matters!
A guideline-driven VTE prevention program (Vermont Model) led to ~60% of high-risk cancer patients receiving prophylactic anticoagulation—resulting in a 60% reduction in VTE and 56% reduction in death. #ISTH2025 #VTEprevention 🩸
@marycushmanmd.bsky.social
A guideline-driven VTE prevention program (Vermont Model) led to ~60% of high-risk cancer patients receiving prophylactic anticoagulation—resulting in a 60% reduction in VTE and 56% reduction in death. #ISTH2025 #VTEprevention 🩸
@marycushmanmd.bsky.social
June 24, 2025 at 7:45 PM
Implementation matters!
A guideline-driven VTE prevention program (Vermont Model) led to ~60% of high-risk cancer patients receiving prophylactic anticoagulation—resulting in a 60% reduction in VTE and 56% reduction in death. #ISTH2025 #VTEprevention 🩸
@marycushmanmd.bsky.social
A guideline-driven VTE prevention program (Vermont Model) led to ~60% of high-risk cancer patients receiving prophylactic anticoagulation—resulting in a 60% reduction in VTE and 56% reduction in death. #ISTH2025 #VTEprevention 🩸
@marycushmanmd.bsky.social
🚨 SPECTACULAR RCT at #ISTH2025!
Although non-inferiority to CTPA wasn’t shown, a negative SPECT V/Q scan led to low 3-month VTE risk—
✅ Supporting the safety of ruling out PE with a SPECT-based algorithm
📸 PE diagnosis rates matched other validated strategies
SPECTacular findings indeed! 🫁💥
Although non-inferiority to CTPA wasn’t shown, a negative SPECT V/Q scan led to low 3-month VTE risk—
✅ Supporting the safety of ruling out PE with a SPECT-based algorithm
📸 PE diagnosis rates matched other validated strategies
SPECTacular findings indeed! 🫁💥
June 24, 2025 at 7:15 PM
🚨 SPECTACULAR RCT at #ISTH2025!
Although non-inferiority to CTPA wasn’t shown, a negative SPECT V/Q scan led to low 3-month VTE risk—
✅ Supporting the safety of ruling out PE with a SPECT-based algorithm
📸 PE diagnosis rates matched other validated strategies
SPECTacular findings indeed! 🫁💥
Although non-inferiority to CTPA wasn’t shown, a negative SPECT V/Q scan led to low 3-month VTE risk—
✅ Supporting the safety of ruling out PE with a SPECT-based algorithm
📸 PE diagnosis rates matched other validated strategies
SPECTacular findings indeed! 🫁💥
🩸 WaVE Study Alert!
In patients with acute CAT & weight >90kg, weight-based dalteparin (200 IU/kg) appears safe & effective.
🔹 Anti-Xa levels aligned with non-obese patients
🔹 Higher levels seen in those with bleeding
Important data to guide dosing CAT & obesity.
📍Presented by Dr. Wang at #ISTH2025
In patients with acute CAT & weight >90kg, weight-based dalteparin (200 IU/kg) appears safe & effective.
🔹 Anti-Xa levels aligned with non-obese patients
🔹 Higher levels seen in those with bleeding
Important data to guide dosing CAT & obesity.
📍Presented by Dr. Wang at #ISTH2025
June 24, 2025 at 7:08 PM
🩸 WaVE Study Alert!
In patients with acute CAT & weight >90kg, weight-based dalteparin (200 IU/kg) appears safe & effective.
🔹 Anti-Xa levels aligned with non-obese patients
🔹 Higher levels seen in those with bleeding
Important data to guide dosing CAT & obesity.
📍Presented by Dr. Wang at #ISTH2025
In patients with acute CAT & weight >90kg, weight-based dalteparin (200 IU/kg) appears safe & effective.
🔹 Anti-Xa levels aligned with non-obese patients
🔹 Higher levels seen in those with bleeding
Important data to guide dosing CAT & obesity.
📍Presented by Dr. Wang at #ISTH2025
📣 ARIVA Trial at #ISTH2025:
🧪 First RCT on antithrombotic therapy post-venous stenting for PTS
🔵 6-month primary patency rate was higher than expected
💊 No added benefit of aspirin + rivaroxaban vs. rivaroxaban alone
www.ahajournals.org/doi/10.1161/...
🧪 First RCT on antithrombotic therapy post-venous stenting for PTS
🔵 6-month primary patency rate was higher than expected
💊 No added benefit of aspirin + rivaroxaban vs. rivaroxaban alone
www.ahajournals.org/doi/10.1161/...
June 24, 2025 at 2:04 PM
📣 ARIVA Trial at #ISTH2025:
🧪 First RCT on antithrombotic therapy post-venous stenting for PTS
🔵 6-month primary patency rate was higher than expected
💊 No added benefit of aspirin + rivaroxaban vs. rivaroxaban alone
www.ahajournals.org/doi/10.1161/...
🧪 First RCT on antithrombotic therapy post-venous stenting for PTS
🔵 6-month primary patency rate was higher than expected
💊 No added benefit of aspirin + rivaroxaban vs. rivaroxaban alone
www.ahajournals.org/doi/10.1161/...
📢 Long-term results from the CELEST trial presented at #ISTH2025:
🧦 No difference in burdensome PTS (~10%) between 25 vs. 35 mmHg ECS after proximal DVT.
✅ Compliance (>50% use) significantly lowers risk.
🔁 Findings reinforce 2-year RCT data.
📌 A placebo-controlled RCT is still needed.
🧦 No difference in burdensome PTS (~10%) between 25 vs. 35 mmHg ECS after proximal DVT.
✅ Compliance (>50% use) significantly lowers risk.
🔁 Findings reinforce 2-year RCT data.
📌 A placebo-controlled RCT is still needed.
June 24, 2025 at 1:48 PM
📢 Long-term results from the CELEST trial presented at #ISTH2025:
🧦 No difference in burdensome PTS (~10%) between 25 vs. 35 mmHg ECS after proximal DVT.
✅ Compliance (>50% use) significantly lowers risk.
🔁 Findings reinforce 2-year RCT data.
📌 A placebo-controlled RCT is still needed.
🧦 No difference in burdensome PTS (~10%) between 25 vs. 35 mmHg ECS after proximal DVT.
✅ Compliance (>50% use) significantly lowers risk.
🔁 Findings reinforce 2-year RCT data.
📌 A placebo-controlled RCT is still needed.
Great provocative SOA by Dr. Eikeilboom: are there settings where warfarin outperforms DOACs in AF?💊
Emerging data suggest lower mortality & better overall clinical benefit in AF with obesity or rheumatic disease, possibly via GAS6 inhibition
#ISTH2025 #AF #Thrombosis
Emerging data suggest lower mortality & better overall clinical benefit in AF with obesity or rheumatic disease, possibly via GAS6 inhibition
#ISTH2025 #AF #Thrombosis
June 24, 2025 at 1:18 PM
Great provocative SOA by Dr. Eikeilboom: are there settings where warfarin outperforms DOACs in AF?💊
Emerging data suggest lower mortality & better overall clinical benefit in AF with obesity or rheumatic disease, possibly via GAS6 inhibition
#ISTH2025 #AF #Thrombosis
Emerging data suggest lower mortality & better overall clinical benefit in AF with obesity or rheumatic disease, possibly via GAS6 inhibition
#ISTH2025 #AF #Thrombosis
🩸 Important findings from Dr @IMYanXu at #ISTH2025:
Black individuals on extended anticoagulation for secondary VTE prevention had higher rates of major bleeding, including ICH, than White individuals.
🔎 No difference in CRNMB.
📢 Calls for action to address racial disparities.
Black individuals on extended anticoagulation for secondary VTE prevention had higher rates of major bleeding, including ICH, than White individuals.
🔎 No difference in CRNMB.
📢 Calls for action to address racial disparities.
June 24, 2025 at 1:18 AM
🩸 Important findings from Dr @IMYanXu at #ISTH2025:
Black individuals on extended anticoagulation for secondary VTE prevention had higher rates of major bleeding, including ICH, than White individuals.
🔎 No difference in CRNMB.
📢 Calls for action to address racial disparities.
Black individuals on extended anticoagulation for secondary VTE prevention had higher rates of major bleeding, including ICH, than White individuals.
🔎 No difference in CRNMB.
📢 Calls for action to address racial disparities.
🧠 #ISTH2025 SCC survey on stroke in cancer patients:
1️⃣ Physicians choose reperfusion strategies differently for patients with vs. without cancer
2️⃣ Antiplatelets remain the most used for secondary prevention
3️⃣ Major equipoise on workup post-stroke in cancer what is the standard of care?
1️⃣ Physicians choose reperfusion strategies differently for patients with vs. without cancer
2️⃣ Antiplatelets remain the most used for secondary prevention
3️⃣ Major equipoise on workup post-stroke in cancer what is the standard of care?
June 23, 2025 at 10:00 PM
🧠 #ISTH2025 SCC survey on stroke in cancer patients:
1️⃣ Physicians choose reperfusion strategies differently for patients with vs. without cancer
2️⃣ Antiplatelets remain the most used for secondary prevention
3️⃣ Major equipoise on workup post-stroke in cancer what is the standard of care?
1️⃣ Physicians choose reperfusion strategies differently for patients with vs. without cancer
2️⃣ Antiplatelets remain the most used for secondary prevention
3️⃣ Major equipoise on workup post-stroke in cancer what is the standard of care?
🩸 New insights from the RENOVE trial (extended duration anticoagulation) at #ISTH2025:
📉 Reduced-dose DOAC is non-inferior in patients with BMI <30, with less bleeding risk.
⚠️ But in patients with BMI ≥30, reduced-dose may be inferior for bleeding and recurrent VTE.
➡️ Dose matters!
@isth.org
📉 Reduced-dose DOAC is non-inferior in patients with BMI <30, with less bleeding risk.
⚠️ But in patients with BMI ≥30, reduced-dose may be inferior for bleeding and recurrent VTE.
➡️ Dose matters!
@isth.org
June 23, 2025 at 8:01 PM
Meta-analysis on GLP-1RA (vs. placebo) and VTE:
🔹 PE rates significantly lower 📉
🔹 VTE rates lower but not statistically significant
🔹 No difference in DVT
🔹 Study design matters: RCTs vs. observational data
Accepted for publication in JTH!
#ISTH2025 #VTE #GLP1RA #Thrombosis
@jthjournal.bsky.social
🔹 PE rates significantly lower 📉
🔹 VTE rates lower but not statistically significant
🔹 No difference in DVT
🔹 Study design matters: RCTs vs. observational data
Accepted for publication in JTH!
#ISTH2025 #VTE #GLP1RA #Thrombosis
@jthjournal.bsky.social
June 23, 2025 at 7:43 PM
Meta-analysis on GLP-1RA (vs. placebo) and VTE:
🔹 PE rates significantly lower 📉
🔹 VTE rates lower but not statistically significant
🔹 No difference in DVT
🔹 Study design matters: RCTs vs. observational data
Accepted for publication in JTH!
#ISTH2025 #VTE #GLP1RA #Thrombosis
@jthjournal.bsky.social
🔹 PE rates significantly lower 📉
🔹 VTE rates lower but not statistically significant
🔹 No difference in DVT
🔹 Study design matters: RCTs vs. observational data
Accepted for publication in JTH!
#ISTH2025 #VTE #GLP1RA #Thrombosis
@jthjournal.bsky.social
Come say hello to David Airdrie, our Executive Director at Thrombosis Canada, at Booth 623! 👋
Learn more about our clinical guides, patient resources, and upcoming education initiatives.
📍 #ISTH2025
We’re here to connect!
#ThrombosisCanada #VTE @thrombosiscan.bsky.social
Learn more about our clinical guides, patient resources, and upcoming education initiatives.
📍 #ISTH2025
We’re here to connect!
#ThrombosisCanada #VTE @thrombosiscan.bsky.social
June 23, 2025 at 7:07 PM
Come say hello to David Airdrie, our Executive Director at Thrombosis Canada, at Booth 623! 👋
Learn more about our clinical guides, patient resources, and upcoming education initiatives.
📍 #ISTH2025
We’re here to connect!
#ThrombosisCanada #VTE @thrombosiscan.bsky.social
Learn more about our clinical guides, patient resources, and upcoming education initiatives.
📍 #ISTH2025
We’re here to connect!
#ThrombosisCanada #VTE @thrombosiscan.bsky.social
📢 Adjust-DVT delivers practice-changing evidence!
Age-adjusted D-dimer safely rules out DVT in patients with low or non-high pretest probability—reducing the need for ultrasounds.
✅ +17% yield in patients ≥75 years
#ISTH2025 #DVT #Thrombosis #VTE
Age-adjusted D-dimer safely rules out DVT in patients with low or non-high pretest probability—reducing the need for ultrasounds.
✅ +17% yield in patients ≥75 years
#ISTH2025 #DVT #Thrombosis #VTE
June 23, 2025 at 2:45 PM
📢 Adjust-DVT delivers practice-changing evidence!
Age-adjusted D-dimer safely rules out DVT in patients with low or non-high pretest probability—reducing the need for ultrasounds.
✅ +17% yield in patients ≥75 years
#ISTH2025 #DVT #Thrombosis #VTE
Age-adjusted D-dimer safely rules out DVT in patients with low or non-high pretest probability—reducing the need for ultrasounds.
✅ +17% yield in patients ≥75 years
#ISTH2025 #DVT #Thrombosis #VTE
🩸 Clots strike twice—often in the same place.
In a study of 708 patients with prior VTE, most recurrent events occurred at the same site as the original, especially in the same leg for prior DVT.
#ISTH2025 #VTE #DVT #Thrombosis
In a study of 708 patients with prior VTE, most recurrent events occurred at the same site as the original, especially in the same leg for prior DVT.
#ISTH2025 #VTE #DVT #Thrombosis
June 23, 2025 at 2:13 PM
🩸 Clots strike twice—often in the same place.
In a study of 708 patients with prior VTE, most recurrent events occurred at the same site as the original, especially in the same leg for prior DVT.
#ISTH2025 #VTE #DVT #Thrombosis
In a study of 708 patients with prior VTE, most recurrent events occurred at the same site as the original, especially in the same leg for prior DVT.
#ISTH2025 #VTE #DVT #Thrombosis