Family Medicine Board Review · Case-Based · Difficult Level

VTE (DVT & PE) — Clinical Vignette MCQs

Board-style cases built from the VTE summary — risk stratification tools, D-dimer math, imaging strategy traps, pregnancy-specific algorithms, and anticoagulant selection. Tap "Reveal Answer" on each, then read the pearl.

15 Questions ●●●● Difficult Single Best Answer
Q1Sudden Death●●●● Very Hard

A 45-year-old man with no known medical history collapses suddenly at home and is declared dead on arrival at the hospital. No autopsy findings are yet available. What diagnosis should always be strongly considered in cases of sudden unexplained death like this?

Reveal Answer

Correct answer: B

VTE is the 3rd most common cause of sudden cardiovascular death (after MI and stroke), and 25% of VTE-related sudden deaths represent the first presentation of VTE — meaning a massive PE can kill without any prior warning signs or diagnosed clot.

Why the others are wrong None of the other options are specifically and classically linked to sudden unexplained collapse and death in this way; PE is the specific "always consider" diagnosis in this clinical scenario.
Exam Pearl PE can be the first and only presentation of VTE, and is a leading cause of sudden cardiovascular death — always keep it on the differential for unexplained sudden collapse/death, even without prior risk factors identified.
Q2Virchow's Triad Classification●●●●● Extreme

A 34-year-old woman with newly diagnosed antiphospholipid syndrome develops a DVT. Which pillar of Virchow's triad does antiphospholipid syndrome primarily represent?

Reveal Answer

Correct answer: C

Antiphospholipid syndrome is specifically listed as an acquired cause of hypercoagulability — the third pillar of Virchow's triad, alongside cancer, pregnancy, and estrogen use.

Why the others are wrong A — venous stasis relates to immobilization, surgery, or long travel, not an autoimmune hypercoagulable state. B — endothelial injury relates to trauma, surgery, or catheters, not this condition. D — it does fit specifically into one of the three pillars. E — inherited hypercoagulability includes Factor V Leiden and prothrombin mutation; antiphospholipid syndrome is specifically categorized as acquired, not inherited.
Exam Pearl Hypercoagulability splits into inherited (Factor V Leiden, prothrombin mutation) and acquired (cancer, pregnancy, estrogen, antiphospholipid syndrome) — know which category each specific risk factor belongs to.
Q3Risk Factor Tiers●●●●● Extreme

A hospitalist is comparing VTE risk between a woman who is currently 20 weeks pregnant and a woman who delivered 2 weeks ago. Which statement about their relative VTE risk tier is most accurate?

Reveal Answer

Correct answer: B

Pregnancy appears in two different risk tiers: antepartum pregnancy is a weak risk factor (OR <2), while pregnancy/postpartum is classified as a moderate risk factor (OR 2–9) — the postpartum period carries meaningfully higher thrombotic risk than pregnancy itself.

Why the others are wrong A — the two states are specifically NOT equal risk; postpartum is higher. C — this reverses the correct relationship; postpartum carries the higher risk. D — both states carry some elevated risk, just at different tiers. E — neither reaches the strong (OR >10) tier, which is reserved for things like major fractures, joint replacement, major trauma, and spinal cord injury.
Exam Pearl Don't treat "pregnancy" as a single risk category — antepartum = weak; postpartum = moderate. This split is a favorite nuanced board distinction.
Q4Wells' DVT Score — Integrative●●●●● Extreme

A 58-year-old man has calf swelling 4 cm greater than the contralateral side, localized tenderness along the deep venous system, pitting edema confined to the symptomatic leg, and was bedridden for 5 days after recent major abdominal surgery 3 weeks ago. No alternative diagnosis is considered as likely. What is his Wells' DVT score and pretest probability category?

Reveal Answer

Correct answer: B

Points: calf swelling >3cm (+1), localized deep venous tenderness (+1), pitting edema confined to symptomatic leg (+1), recently bedridden >3 days or major surgery within 12 weeks (+1) = total 4 points. Since >2 = high probability, his score of 4 places him in the high probability category.

Why the others are wrong A/C — miscalculate either the point total or the probability category; a score of 4 is high, not moderate. D — this would require the "alternative diagnosis as likely or more likely" criterion (−2), which isn't present here since no alternative diagnosis is considered as likely. E — overcounts the points; only 4 specific criteria are met in this vignette.
Exam Pearl Practice adding up Wells' DVT criteria directly from a vignette: each positive finding = +1 (except alternative diagnosis = −2). Score >2 = high probability → go straight to compression ultrasound, skip D-dimer.
Q5Age-Adjusted D-Dimer — Calculation●●●●● Extreme

A 68-year-old woman with low pretest probability for DVT has a D-dimer level of 620 µg/L. Using the age-adjusted cutoff, is this result positive or negative?

Reveal Answer

Correct answer: B

The age-adjusted D-dimer cutoff for patients >50 years is calculated as Age × 10 µg/L. For this 68-year-old: 68 × 10 = 680 µg/L. Her result of 620 µg/L falls below this age-adjusted threshold, making it negative despite exceeding the standard (age-independent) cutoff of 500.

Why the others are wrong A — this uses the standard cutoff rather than the more appropriate age-adjusted cutoff for a patient over 50. C — the age-adjusted cutoff specifically applies to patients over 50, not under. D — the calculation only requires her age (68 × 10 = 680), which is fully given. E — this is an overgeneralization; the age-adjusted cutoff is calculated specifically per patient (age × 10), not a blanket negative for anyone over 65.
Exam Pearl Age-adjusted D-dimer formula: Age × 10 µg/L (for age >50). Practice this exact calculation — boards love testing whether you can correctly apply it rather than just recognize it exists.
Q6DVT Imaging — Overdiagnosis Trap●●●●● Extreme

A resident recommends whole-leg ultrasound instead of proximal compression ultrasound for a low-risk patient with mild calf discomfort, reasoning that it is "more thorough" and would catch more cases. Is this the best approach?

Reveal Answer

Correct answer: B

Whole-leg ultrasound may overdiagnose distal DVT — many distal DVTs are clinically insignificant and may resolve spontaneously. This can lead to unnecessary anticoagulation and bleeding risk, so it's best avoided in low-risk patients unless symptoms worsen. The preferred strategy in this scenario is proximal compression ultrasound (assessing femoral/popliteal veins), with a repeat scan in 7 days if initially negative and clinical suspicion remains.

Why the others are wrong A — "more thorough" isn't automatically better; it specifically risks overdiagnosis and overtreatment in this context. C — proximal ultrasound, combined with the 7-day repeat strategy, is a validated and preferred approach for appropriate-risk patients. D — ultrasound (specifically compression ultrasound) is the first-line imaging modality for DVT. E — this isn't an age-based exception; it's a risk-level-based consideration.
Exam Pearl "More imaging" is not always better. Whole-leg ultrasound's downside (overdiagnosis of insignificant distal clots → unnecessary anticoagulation) is a classic board trap testing whether you understand the harms of overtesting.
Q7PERC Rule Application●●●●● Extreme

A 29-year-old man has mild, non-worsening dyspnea with a Wells PE score of 0 (low risk). He is afebrile, HR 78, O₂ sat 99% on room air, no hemoptysis, no hormone use, no prior VTE, no recent surgery/trauma, and no leg swelling. What is the most appropriate next step?

Reveal Answer

Correct answer: B

With a low Wells PE score, the PERC rule can be applied. Since he meets none of the PERC criteria (age <50, HR <100, room air O₂ sat ≥95%, no hemoptysis, no hormone use, no prior VTE, no recent surgery/trauma, no leg swelling), his PERC score is 0, which has a >98.5% negative predictive value for excluding PE — no further workup, including D-dimer, is indicated.

Why the others are wrong A — proceeding directly to CTPA in a PERC-negative, low-risk patient exposes him to unnecessary radiation/contrast without meaningful diagnostic benefit. C — a D-dimer isn't needed when PERC is entirely negative in a low-risk patient; this is the entire point of using PERC to stop the workup early. D — admission isn't indicated based on this reassuring risk stratification. E — PERC is specifically designed for and applicable to low-pretest-probability patients like this one.
Exam Pearl Low pretest probability + PERC-negative (all 8 criteria absent) = stop the workup, no D-dimer or imaging needed. This is one of the most efficient "avoid unnecessary testing" tools in emergency/primary care medicine.
Q8Wells' PE Score — Integrative●●●●● Extreme

A 50-year-old woman presents with acute dyspnea. PE is considered the most likely diagnosis. Her heart rate is 108 bpm. She has no clinical signs of DVT, no immobilization/recent surgery, no prior PE/DVT, no hemoptysis, and no active malignancy. What is her Wells' PE score and risk category?

Reveal Answer

Correct answer: A

Points: PE is #1 diagnosis or equally likely (+3), heart rate >100 bpm (+1.5) = total 4.5 points. Per Wells' PE interpretation (low: 0–1, moderate: 2–6, high: >6), her score of 4.5 falls into the moderate probability category.

Why the others are wrong B — undercounts her actual score (3 vs. the correct 4.5) and misclassifies risk. C — overcounts points not actually present in this vignette (no DVT signs, no immobilization, no prior VTE, no hemoptysis, no malignancy). D — this significantly undercounts by omitting the "PE is #1 diagnosis" criterion (+3), the largest single contributor. E — correctly calculates 4.5 but misclassifies it as high (it's moderate; high requires >6).
Exam Pearl Wells' PE point values aren't all equal — the two "big" criteria (clinical DVT signs = 3, PE as most likely diagnosis = 3) dominate the score. Practice adding these directly from clinical vignettes, and remember: low 0–1, moderate 2–6, high >6.
Q9PE Size ≠ Severity●●●●● Extreme

Two patients are diagnosed with PE on CTPA. Patient A has a small subsegmental clot but shows signs of right ventricular strain and borderline hypotension. Patient B has a large, extensive clot burden but is hemodynamically stable with normal vitals and no RV strain. Which patient is at higher immediate risk?

Reveal Answer

Correct answer: B

PE size is not equal to PE severity. A small clot with RV strain represents high risk, while a large clot with stable vitals represents comparatively lower risk. Hemodynamic status matters more than clot size when assessing PE severity and guiding management intensity.

Why the others are wrong A/E — both incorrectly prioritize clot burden over hemodynamic/RV strain findings, which are the more important severity determinants. C — the two patients have clearly different risk profiles based on their hemodynamic and RV strain findings, not identical risk. D — hemodynamic status and RV strain, not exact clot location, are the key severity determinants described in this framework.
Exam Pearl PE severity = hemodynamics + RV strain, NOT clot size. This concept frequently appears as a "which patient is sicker" trap question pairing a small-but-unstable clot against a large-but-stable one.
Q10V/Q Scan Indications●●●○ Hard

Which of the following patients with suspected PE is the best candidate for a V/Q scan rather than CTPA?

Reveal Answer

Correct answer: B

V/Q scanning is specifically indicated when CTPA is contraindicated or less optimal: pregnancy, contrast allergy, or CKD (GFR <30). A pregnant patient is the classic scenario where V/Q scanning is preferred, minimizing radiation exposure to breast tissue compared to CTPA (though overall fetal radiation is low with either).

Why the others are wrong A/C/E — none of these patients have a specific contraindication to CTPA (normal renal function, no contrast allergy); CTPA (the gold standard) remains preferred for them. D — test selection should be based on clinical contraindications, not simply patient preference for speed.
Exam Pearl V/Q scan indications: pregnancy, contrast allergy, CKD (GFR <30). In pregnancy specifically, workup begins with a chest x-ray, followed by perfusion/ventilation imaging as needed.
Q11YEARS Algorithm — Pregnancy PE●●●●● Extreme

A 30-year-old pregnant woman at 26 weeks' gestation has suspected PE. She has no clinical signs of DVT, PE is not felt to be the most likely diagnosis, and she has no hemoptysis (zero YEARS clinical criteria met). Her D-dimer is 800 ng/mL. Using the YEARS algorithm, is PE ruled out?

Reveal Answer

Correct answer: A

Per the YEARS algorithm for suspected PE in pregnancy: with no clinical criteria met, PE is ruled out if D-dimer is <1000 ng/mL. Her level of 800 ng/mL falls below this threshold, so PE is ruled out without further imaging.

Why the others are wrong B — this ignores the YEARS-specific, criteria-dependent threshold system designed specifically for pregnancy. C — while general D-dimer testing is described as unreliable for DVT in pregnancy, the YEARS algorithm specifically incorporates D-dimer with adjusted thresholds for suspected PE; it isn't ignored entirely. D — the 500 ng/mL threshold applies when ≥1 criterion is met, not when zero criteria are met (which uses the higher 1000 ng/mL threshold). E — the YEARS algorithm is specifically designed for and applicable to suspected PE in pregnancy.
Exam Pearl YEARS algorithm for pregnancy PE: 0 criteria met → D-dimer <1000 ng/mL rules out PE; ≥1 criterion met → D-dimer <500 ng/mL rules out PE. If exceeded, proceed to CTPA or V/Q. If DVT is confirmed on ultrasound, treat as PE without chest imaging.
Q12Outpatient PE Treatment — sPESI/CHEST●●●●● Extreme

A 45-year-old man with confirmed segmental PE has no history of cancer or chronic cardiopulmonary disease, O₂ saturation 96%, pulse 88 bpm, systolic BP 118 mmHg, and age 45. He feels well, has no bleeding risk, normal platelet count, is expected to be adherent, and has reliable outpatient follow-up available. What is his sPESI score, and is he a candidate for outpatient management?

Reveal Answer

Correct answer: B

None of the sPESI criteria are met (age not >80, no cancer history, no chronic cardiopulmonary disease, O₂ sat not <90%, pulse not ≥110, systolic BP not <100) — sPESI score = 0, corresponding to low mortality risk (1.1%). Combined with meeting all CHEST outpatient criteria (stable, no bleeding/severe organ disease/thrombocytopenia, expected adherence, feels well, reliable follow-up), he is an appropriate outpatient treatment candidate.

Why the others are wrong A/C — both significantly overcount his sPESI score; none of the listed criteria apply to him. D — troponin isn't part of the sPESI calculation itself (sPESI uses age, cancer history, cardiopulmonary disease history, O₂ sat, pulse, and systolic BP). E — a score of 1 wouldn't apply here (his true score is 0), and even a score of 0 doesn't "automatically" mandate outpatient care without also confirming CHEST criteria and appropriate social factors — it just makes him eligible for consideration.
Exam Pearl Outpatient PE eligibility requires BOTH: sPESI score of 0 (low mortality risk) AND meeting the CHEST safety-of-home-management criteria. Practice calculating sPESI directly from vignette vitals/history.
Q13Anticoagulant Selection — Renal Function●●●●● Extreme

Three patients with newly diagnosed PE have different renal function: Patient A has a CrCl of 45 mL/min, Patient B has a CrCl of 20 mL/min, and Patient C is on dialysis. What is the most appropriate anticoagulant strategy for each?

Reveal Answer

Correct answer: B

Renal function-based anticoagulant selection: CrCl ≥30 → DOAC can be used (Patient A); CrCl 15–29 → avoid DOAC, adjust LMWH dose (Patient B); CrCl <15 or dialysis → unfractionated heparin (UFH) + warfarin (Patient C).

Why the others are wrong A — DOACs are not appropriate across the board regardless of renal function; Patients B and C require different strategies. C — UFH + warfarin is specifically reserved for the most severe renal impairment (CrCl <15/dialysis), not needed for Patient A with preserved renal function. D — full-dose rivaroxaban in a dialysis patient is inappropriate and unsafe; this population should use UFH + warfarin instead. E — renal function is specifically a primary determinant of anticoagulant choice in this framework.
Exam Pearl Renal-based anticoagulant ladder: CrCl ≥30 → DOAC; CrCl 15–29 → avoid DOAC, adjust LMWH; CrCl <15/dialysis → UFH + warfarin. Note: apixaban is a notable exception with no dose adjustment needed even in dialysis, per its individual dosing profile — but this general renal ladder still guides overall class selection.
Q14Warfarin Bridging Rules●●●●● Extreme

A patient with acute DVT is started on warfarin and heparin simultaneously. On day 4, her INR is 2.3. Her physician considers discontinuing the heparin bridge at this point. Is this appropriate?

Reveal Answer

Correct answer: B

Warfarin bridging rules require overlap of at least 5 days AND INR ≥2 for at least 24 hours before discontinuing the heparin bridge. On day 4, even with a therapeutic INR of 2.3, the minimum 5-day overlap has not yet been reached — heparin should be continued until both conditions are satisfied.

Why the others are wrong A — an adequate INR alone isn't sufficient; the minimum overlap duration (5 days) must also be met. C — heparin discontinuation isn't based on a fixed 3-day rule regardless of INR; both the overlap duration and INR criteria must be satisfied together. D — simultaneous warfarin + heparin (bridging) is specifically the standard, recommended approach when initiating warfarin, given warfarin's delayed onset of anticoagulant effect and initial paradoxical procoagulant state. E — INR is specifically one of the two required criteria for stopping the bridge.
Exam Pearl Warfarin bridging rule: start with heparin; overlap ≥5 days AND INR ≥2 for 24 hours before stopping heparin; target INR range 2–3. Both conditions (duration AND INR) must be met together — meeting one early doesn't shorten the requirement for the other.
Q15Special Population — Antiphospholipid Syndrome●●●●● Extreme

A 40-year-old woman with confirmed antiphospholipid antibody syndrome develops an acute DVT. Her physician is deciding between a DOAC and LMWH/warfarin for treatment. What is the most appropriate choice, and why?

Reveal Answer

Correct answer: B

LMWH or warfarin is specifically preferred over DOACs in patients with antiphospholipid antibody syndrome (along with those with severe liver disease and coagulopathy) — DOACs have shown inferior outcomes in this specific population in clinical evidence.

Why the others are wrong A — while DOACs are generally first-line for most VTE patients, antiphospholipid syndrome is a specific, named exception where LMWH/warfarin is preferred instead. C — an acute DVT requires anticoagulation regardless of the underlying hypercoagulable condition; withholding treatment is inappropriate. D — aspirin alone is not adequate treatment for an acute, confirmed DVT. E — the specific choice of anticoagulant class is clinically significant in this population, contrary to this statement.
Exam Pearl Two named exceptions where LMWH/warfarin is preferred over DOACs: antiphospholipid antibody syndrome and severe liver disease with coagulopathy. Contrast this with active cancer, where DOACs are actually the preferred agent — don't confuse these two special populations.
VTE (DVT & PE) Board Review · Case-Based MCQ Set · 15/15 Questions