Table 2.
Physician Examination and Testing Characteristics of Patients Diagnosed with Acute Pulmonary Embolism in Primary Care, Stratified by Initial Site-of-Care Decision: Clinic Only Versus Referral to a Higher Level of Care
| Characteristics | Total cohort (n = 652) | Clinic only (n = 134) | Referred to the ED or hospital (n = 518) | p value |
|---|---|---|---|---|
| Index encounter, mode, n (%) | 0.55 | |||
| In-person | 586 (89.9) | 120 (89.6) | 466 (90.0) | |
| Telemedicine (secure message or telephone) | 61 (9.4) | 12 (9.0) | 49 (9.5) | |
| None* | 5 (0.8) | 2 (1.5) | 3 (0.6) | |
| Index physical examination findings, n (%) | ||||
| N† | 586 (89.9) | 120 (89.6) | 466 (90.0) | |
| Systolic blood pressure < 100 mmHg | 19 (3.2) | 7 (5.8) | 12 (2.6) | 0.072 |
| Systolic blood pressure ≥ 160 mmHg | 4 (0.7) | 0 (0) | 4 (0.8) | 0.31 |
| Heart rate ≥ 110 beats/min | 43 (7.3) | 4 (3.3) | 39 (8.4) | 0.059 |
| Temperature < 36 °C | 5 (0.8) | 0 (0) | 5 (1.1) | 0.26 |
| Temperature ≥ 38 °C | 0 (0) | 0 (0) | 0 (0) | |
| Pulse oximetry < 90%‡ | 4 (0.7) | 0 (0) | 4 (0.9) | 0.31 |
| Respiratory rate documented | 24 (4.1) | 5 (4.2) | 19 (4.1) | 0.96 |
| Rate ≥ 30 breaths/min | 1 (4.2) | 0 (0) | 1 (5.3) | 0.60 |
| Altered mental status§ | 2 (0.3) | 0 (0) | 2 (0.4) | 0.47 |
| D-Dimer, n (%) | 0.21 | |||
| Elevated | 320 (49.1) | 60 (44.8) | 260 (50.2) | |
| Negative | 4 (0.6) | 2 (1.5) | 2 (0.4) | |
| Missing | 328 (50.3) | 72 (53.7) | 256 (49.4) | |
| Troponin, n (%)‖ | 0.30 | |||
| Elevated | 0 (0) | 0 (0) | 0 (0) | |
| Negative | 42 (6.4) | 6 (4.5) | 36 (7.0) | |
| Missing | 610 (93.6) | 128 (95.5) | 482 (93.1) | |
| B-type natriuretic peptide, n (%) | 0.22 | |||
| ≥ 500 pg/mL | 3 (0.5) | 1 (0.8) | 2 (0.4) | |
| ≥ 100 < 500 pg/mL | 42 (6.4) | 5 (3.7) | 37 (7.1) | |
| < 100 pg/mL | 112 (17.2) | 18 (13.4) | 94 (18.2) | |
| Missing | 495 (75.9) | 110 (82.1) | 385 (74.3) | |
| Index 12-lead electrocardiogram, n (%) | 0.44 | |||
| No change from prior | 15 (2.3) | 5 (3.7) | 10 (1.9) | |
| Normal | 58 (8.9) | 15 (11.2) | 43 (8.3) | |
| Tachycardia | 12 (1.8) | 1 (0.8) | 11 (2.1) | |
| Other finding | 24 (3.7) | 5 (3.7) | 19 (3.7) | |
| Not obtained | 543 (83.3) | 108 (80.6) | 435 (84.0) | |
| Compression ultrasonography, n (%) | 0.19 | |||
| Yes, negative for deep vein thrombosis | 28 (4.3) | 9 (6.7) | 19 (3.7) | |
| Yes, positive for deep vein thrombosis | 42 (6.4) | 6 (4.5) | 36 (7.0) | |
| Not obtained | 582 (89.3) | 119 (88.8) | 463 (89.4) | |
| Diagnostic imaging, n (%) | 0.44 | |||
| CTPA | 617 (94.6) | 125 (93.3) | 492 (95) | |
| Ventilation/perfusion scan | 35 (5.4) | 9 (6.7) | 26 (5.0) | |
| Clinician ordering diagnostic imaging, n (%) | 0.059 | |||
| Primary care clinician | 500 (76.7) | 111 (82.8) | 389 (75.1) | |
| Colleague | 152 (23.3) | 23 (17.2) | 129 (24.9) | |
| Day of imaging, n (%) | 0.098 | |||
| Monday–Friday | 626 (96.0) | 132 (98.5) | 494 (95.4) | |
| Saturday–Sunday | 26 (4.0) | 2 (1.5) | 24 (4.6) | |
| Time of imaging, n (%) | 0.009 | |||
| 0800 < 1600 | 418 (64.1) | 105 (78.4) | 313 (60.4) | |
| 1600 < 0800 | 234 (35.9) | 29 (21.6) | 205 (39.6) | |
| CTPA clot location¶, n (%) | < 0.001 | |||
| Proximal | 256 (39.3) | 25 (18.7) | 231 (44.6) | |
| Distal | 355 (54.5) | 98 (73.1) | 257 (49.6) | |
| Subsegmental only | 65 (10.0) | 30 (22.4) | 35 (6.8) | |
| Unclear or missing | 41 (6.3) | 11 (8.2) | 30 (5.8) | |
| Radiologist comment on heart from CTPA, n (%) | 0.002 | |||
| Heart normal or right ventricular strain absent | 338 (51.8) | 62 (46.3) | 276 (53.3) | |
| Right ventricular strain present | 24 (3.7) | 2 (1.5) | 22 (4.3) | |
| Heart enlarged | 38 (5.8) | 2 (1.5) | 36 (6.9) | |
| Equivocal, not reported, blank, or other | 252 (38.7) | 68 (50.8) | 184 (35.5) | |
| Pulmonary Embolism Severity Index Class, n (%) | 0.79 | |||
| I–II (lower risk) | 378 (58.0) | 74 (55.2) | 304 (58.7) | |
| III–IV (intermediate risk) | 179 (27.5) | 41 (30.6) | 138 (26.6) | |
| V (higher risk) | 29 (4.4) | 5 (3.7) | 24 (4.6) | |
| Missing | 66 (10.1) | 14 (10.4) | 52 (10.0) | |
| Echocardiography, n (%)# | 129 (19.8) | 1 (0.07) | 128 (24.7) | < 0.0001 |
| Telephone consultation with pulmonologist or hematologist after diagnosis secured, n (%) | 60 (9.2) | 44 (32.8) | 16 (3.1) | < 0.001 |
CTPA computed tomography pulmonary angiography, ED emergency department
*Several patients with an incidental diagnosis of acute pulmonary embolism had their imaging study ordered by primary care without an index encounter
†Physical examination findings reported only for patients who had an in-person initial encounter; excludes those who had a telemedicine encounter or had no index encounter at all
‡Includes post-exertional pulse oximetry measurements
§Disorientation, lethargy, stupor, or coma
‖Troponin and B-type natriuretic peptide were obtained prior to the diagnosis of pulmonary embolism. Serum troponin values were obtained using a fourth-generation troponin I assay. Values above the 99th percentile were considered elevated
¶We defined proximal as clearly lobar or more proximal. Pulmonary embolism described as lobar or segmental was categorized as distal. Those described as “either segmental or subsegmental” were not categorized as subsegmental. Location was missing in 41 patients: it was unclear on CTPA in 6 patients; it was unavailable in 35 patients who were diagnosed by ventilation-perfusion scintigraphy
#We identified echocardiograms obtained at the time of or shortly following the diagnosis of pulmonary embolism