Little is known about the relation between type A acute aortic dissection (TAAAD) and pulse pressure (PP), defined as the difference between systolic and diastolic blood pressure. In this study, we explored the association between PP and presentation, complications, and outcomes of patients with TAAAD. PP at hospital presentation was used to divide 1,960 patients with noniatrogenic TAAAD into quartiles: narrowed (≤39 mm Hg, n = 430), normal (40 to 56 mm Hg, n = 554), mildly elevated (57 to 75 mm Hg, n = 490), and markedly elevated (≥76 mm Hg, n = 486). Variables relating to index presentation and in-hospital outcomes were analyzed. Patients with TAAAD in the narrowed PP quartiles were frequently older and Caucasian, whereas patients with markedly elevated PPs tended to be male and have a history of hypertension. Patients who demonstrated abdominal vessel involvement more commonly demonstrated elevated PPs, whereas patients with narrowed PPs were more likely to have periaortic hematoma and/or pericardial effusion. Narrowed PPs were also correlated with greater incidences of hypotension, cardiac tamponade, and mortality. Patients with TAAAD who were managed with endovascular and hybrid procedures and those with renal failure tended to have markedly elevated PPs. No difference in aortic regurgitation at presentation was noted among groups. In conclusion, patients with TAAAD in the third PP quartile had better in-hospital outcomes than patients in the lowest quartile. Patients with narrowed PPs experienced more cardiac complications, particularly cardiac tamponade, whereas those with markedly elevated PPs were more likely to have abdominal aortic involvement. Presenting PP offers a clue to different manifestations of acute aortic dissection that may facilitate initial triage and care.
Pulse pressure (PP) has been the focus of a number of studies in several populations of cardiovascular disease. PP, the force that a heart generates with each contraction, is defined as the difference between systolic and diastolic blood pressure. Wide PP is strongly correlated with long standing hypertension where there is a loss of aortic elasticity in chronic disease. Wide PP has been associated with cardiovascular, coronary, and all-cause mortality in various patient populations. A narrow PP at hospital admission is an independent predictor of mortality in patients with acute coronary syndrome. Little is known about the relation between PP and type A acute aortic dissection (TAAAD). We hypothesized that patients with TAAAD who presented with a narrow PP would be more likely to have cardiac tamponade and experience negative outcomes and increased mortality compared with patients who exhibited normal and mildly elevated PPs. We also believe that patients with a wide PP might have increased age, more malperfusion, or aortic valve disruption leading to aortic valve regurgitation and worse outcomes.
Methods
The International Registry of Acute Aortic Dissection (IRAD) has collected data on patients with acute aortic dissection at 24 aortic referral centers in 11 countries since January 1, 1996. Patients are enrolled if they present with nontraumatic, spontaneous, or iatrogenic dissections within 14 days of symptom onset. They are identified prospectively by physicians or retrospectively through discharge diagnoses, imaging, and/or surgical databases. Diagnosis is based on symptom onset, patient history, imaging, surgical examination, and/or autopsy. All sites have received approval from each hospital’s institutional review board to participate in IRAD. A comprehensive description of the organization and methods of the IRAD database have been detailed previously.
A standardized form with 290 variables was used to record information on patient demographics, medical history, clinical presentation, physical findings, imaging study results, medical and interventional management, and in-hospital outcomes. Data were collected at presentation or retrospectively through medical record analysis and reviewed for face validity and completeness at the coordinating center at the University of Michigan.
This study included patients with TAAAD enrolled in IRAD from January 1, 1996 to July 26, 2012. Patients with type B dissections and/or iatrogenic dissections were excluded, resulting in 1,960 study patients. These patients were arranged into quartiles based on PP at hospital presentation: narrow (≤39 mm Hg, n = 430), normal (40 to 56 mm Hg, n = 554), mildly elevated (57 to 75 mm Hg, n = 490), and markedly elevated (≥76 mm Hg, n = 486). When patients fell between quartiles, they were assigned to the higher grouping resulting in a slightly uneven sample size between quartiles.
Categorical variables were compared across PP quartiles using Pearson’s chi-square test or Fisher’s exact test as appropriate. Continuous variables were examined using analysis of variance. Linear-by-linear association was used to study linear trends across quartiles. The tables are marked with an asterisk to indicate variables that have both a p value of <0.05 and a linear-by-linear association of <0.05. Variables detailing demographics, patient history, presentation, imaging results, complications, and outcomes were analyzed for their relation to PP in patients with TAAAD. All statistical analyses were performed using SPSS, version 20.0 (IBM Corp.).
Results
The study cohort consisted of 1,960 subjects with TAAAD including 21.9% of patients in the narrow quartile, 28.3% in the normal quartile, 25.0% in the mildly elevated quartile, and 24.8% in the markedly elevated quartile. Patients in the narrow quartile (PP ≤39 mm Hg) were typically aged >70 years, women, a race other than Caucasian, and had an average age of 63.6 years ( Table 1 ). Patients in the markedly elevated quartile (PP ≥76 mm Hg) had an average age of 60.8 years and tended to be Caucasian, men, and have a history of hypertension ( Table 1 ). There was no correlation seen between PP and a history of atherosclerosis, previous smoking, or any previously diagnosed aortic conditions ( Table 1 ).
| Variable | PP (mm Hg) | p Value | |||
|---|---|---|---|---|---|
| ≤39 | 40–56 | 57–75 | ≥76 | ||
| Number of patients | 430 (21.9) | 554 (28.2) | 490 (25.0) | 486 (24.8) | — |
| Demographics | |||||
| Age (yrs) | 63.6 ± 13.477 | 62.04 ± 14.848 | 59.74 ± 14.794 | 60.78 ± 13.640 | <0.001 ∗ |
| Age (≥70 yrs) | 147 (34.2) | 183 (33.0) | 124 (25.3) | 134 (27.6) | 0.006 ∗ |
| Men | 276 (64.2) | 361 (65.2) | 339 (69.2) | 357 (73.5) | 0.008 ∗ |
| White | 376 (91.7) | 468 (90.0) | 404 (87.4) | 378 (84.6) | 0.006 ∗ |
| History | |||||
| Hypertension | 301 (71.7) | 382 (69.8) | 350 (72.5) | 385 (79.9) | 0.002 ∗ |
| Atherosclerosis | 94 (22.7) | 106 (19.8) | 83 (17.5) | 104 (21.7) | 0.224 |
| The Marfan syndrome | 13 (3.1) | 31 (5.7) | 30 (6.2) | 14 (2.9) | 0.021 |
| Bicuspid aortic valve | 17 (4.6) | 20 (4.3) | 16 (3.9) | 15 (3.7) | 0.924 |
| Other aortic disease | 9 (2.1) | 8 (1.5) | 8 (1.7) | 6 (1.3) | 0.756 |
| Smoker: current | 34 (28.3) | 54 (36.2) | 46 (32.4) | 54 (37.2) | 0.409 |
| Cocaine abuse | 4 (1.0) | 8 (1.5) | 8 (1.7) | 9 (1.9) | 0.702 |
| Family history of aortic disease | 9 (6.2) | 17 (9.2) | 23 (14.3) | 10 (6.1) | 0.036 |
| Known aortic aneurysm | 50 (12.1) | 73 (13.5) | 54 (11.3) | 49 (10.2) | 0.403 |
| Previous aortic dissection | 13 (3.1) | 20 (3.7) | 22 (4.6) | 19 (4.0) | 0.704 |
| Aortic aneurysm/dissection surgery | 22 (5.2) | 37 (6.9) | 30 (6.3) | 31 (6.5) | 0.742 |
| Previous cardiac surgery | 41 (9.7) | 69 (12.9) | 58 (12.3) | 69 (14.4) | 0.191 |
∗ Variables that have both a p value of <0.05 and a linear-by-linear association of <0.05.
Patients who presented with a narrow PP tended to have more cardiac complications in comparison with those in the other 3 quartiles ( Tables 2 and 3 ). Specifically, they had greater incidences of periaortic hematoma, pericardial effusion, and cardiac tamponade than patients with normal, mildly elevated, and markedly elevated PPs ( Table 3 ). Patients with TAAAD in the narrow PP quartile had a greater risk of in-hospital mortality than patients in the other quartiles ( Figure 1 ). There was no relation between narrow PP and false lumen patency, coronary artery compromise, or long-term mortality ( Tables 2 and 3 ).
| Variable | PP (mm Hg) | p Value | |||
|---|---|---|---|---|---|
| ≤39 | 40–56 | 57–75 | ≥76 | ||
| True intramural hematoma on first imaging study | 21 (5.3) | 26 (5.1) | 17 (3.7) | 17 (3.9) | 0.567 |
| True intramural hematoma progressing to dissection | 4 (19.0) | 4 (16.0) | 3 (17.6) | 2 (14.3) | 1.000 |
| Intramural hematoma (any study) | 81 (18.8) | 112 (20.2) | 84 (17.1) | 76 (15.6) | 0.248 |
| Pre-/postoperative extension of dissection | 38 (9.4) | 40 (7.7) | 34 (7.3) | 35 (7.6) | 0.679 |
| Any aneurysm | 198 (51.0) | 259 (51.8) | 230 (51.3) | 220 (50.2) | 0.971 |
| False lumen patency | |||||
| Patent | 193 (72.3) | 272 (71.0) | 222 (73.3) | 228 (71.0) | 0.905 |
| Partial thrombosis | 44 (16.5) | 66 (17.2) | 61 (20.1) | 67 (20.9) | 0.423 |
| Complete thrombosis | 30 (11.2) | 45 (11.7) | 20 (6.6) | 26 (8.1) | 0.075 |
| Abdominal vessel involvement | 94 (22.1) | 95 (17.3) | 101 (20.8) | 133 (27.6) | 0.001 ∗ |
| Right renal | 26 (6.1) | 35 (6.4) | 36 (7.4) | 45 (9.3) | 0.206 |
| Left renal | 56 (13.1) | 48 (8.7) | 59 (12.1) | 85 (17.6) | <0.001 ∗ |
| Distal communication | 69 (27.2) | 92 (26.3) | 73 (26.7) | 83 (28.8) | 0.906 |
| Arch vessel involvement | 147 (46.2) | 166 (39.2) | 128 (37.0) | 135 (37.2) | 0.052 |
| Coronary artery compromised | 32 (9.9) | 53 (12.8) | 35 (10.2) | 48 (13.6) | 0.337 |
∗ Variables that have both a p value of <0.05 and a linear-by-linear association of <0.05.
| Variable | PP (mm Hg) | p Value | |||
|---|---|---|---|---|---|
| ≤39 | 40–56 | 57–75 | ≥76 | ||
| Management | |||||
| Medical | 51 (11.9) | 75 (13.5) | 54 (11.0) | 57 (11.7) | 0.642 |
| Surgical | 372 (86.5) | 475 (85.7) | 426 (87.1) | 410 (84.4) | 0.639 |
| Endovascular | 4 (0.9) | 1 (0.2) | 7 (1.4) | 9 (1.9) | 0.031 ∗ |
| Hybrid | 3 (0.7) | 3 (0.5) | 2 (0.4) | 10 (2.1) | 0.047 ∗ |
| Complications | |||||
| Aortic regurgitation | 194 (55.1) | 239 (51.3) | 231 (57.5) | 241 (57.5) | 0.139 |
| Periaortic hematoma | 105 (30.2) | 93 (20.2) | 70 (17.9) | 70 (17.7) | <0.001 ∗ |
| Pericardial effusion | 224 (58.8) | 235 (47.2) | 153 (35.1) | 138 (32.2) | <0.001 ∗ |
| Cerebrovascular accident: 1-h outcome | 41 (10.5) | 43 (8.7) | 36 (8.1) | 41 (9.3) | 0.653 |
| Coma: 1-h outcome | 8 (2.1) | 14 (2.8) | 6 (1.4) | 9 (2.1) | 0.478 |
| Spinal cord ischemia | 4 (1.0) | 4 (0.8) | 4 (0.9) | 4 (0.9) | 0.986 |
| Myocardial ischemia | 51 (12.4) | 61 (11.6) | 53 (11.3) | 35 (11.3) | 0.078 |
| Myocardial infarction | 33 (8.0) | 33 (6.3) | 29 (6.2) | 20 (4.3) | 0.152 |
| Mesenteric ischemia/infarction | 25 (6.1) | 30 (5.7) | 19 (4.1) | 36 (7.7) | 0.126 |
| Pre-/postoperative renal failure | 102 (24.9) | 141 (26.7) | 94 (20.1) | 136 (29.1) | 0.014 ∗ |
| Pre-/postoperative extension of dissection | 38 (9.4) | 40 (7.7) | 34 (7.3) | 35 (7.6) | 0.680 |
| Pre-/postoperative hypotension | 223 (53.9) | 171 (32.4) | 79 (17.0) | 77 (16.6) | <0.001 ∗ |
| Cardiac tamponade | 32 (7.5) | 17 (3.1) | 0 (0.0) | 3 (0.6) | <0.001 ∗ |
| Limb ischemia | 56 (13.8) | 56 (10.7) | 57 (12.2) | 74 (15.9) | 0.097 |
| Complications (any) | 34 (8.0) | 33 (6.0) | 27 (5.6) | 44 (9.1) | 0.099 |
| In-hospital mortality | 133 (30.9) | 141 (25.5) | 80 (16.3) | 114 (23.5) | <0.001 ∗ |
| Cause of death: aortic rupture | 23 (26.7) | 27 (29.7) | 16 (29.1) | 15 (21.7) | 0.700 |
| 5-yr Kaplan-Meier survival estimates (n at risk) | 77.7 (19) | 81.0 (21) | 84.5 (19) | 84.2 (16) | 0.507 |
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