Clinical and pathologic findings of aortic dissection at autopsy: Review of 336 cases over nearly 6 decades

Successful Primary PCI in Stanford Type A Aortic Dissection Complicated by Inferior ST-Elevation Myocardial Infarction: A Case in a Facility with No Surgical Backup

Mortality of type A aortic dissection (TAAD) complicated with coronary malperfusion syndrome is very high even when emergency surgery is performed. Several reports suggested that primary percutaneous coronary intervention (PPCI) followed by immediate corrective surgery may reduce mortality. In many countries, immediate transfer to an aortic surgery center may not be possible. We report a case of TAAD complicated by coronary malperfusion successfully treated with PPCI followed by elective corrective surgery. A 48-year-old man was referred to emergency department with acute inferior ST-elevation myocardial infarction (STEMI) and underwent PPCI. During the procedure, we realized that the cause of STEMI was TAAD. We decided to continue because the patient experienced seizures and bradycardia. Subsequently, echocardiography and computed tomography confirmed the dissection. The patient was discharged and referred to the National Cardiovascular Center where he underwent successful elective surgery. In this patient, immediate revascularization was lifesaving and served as a bridging procedure before surgical correction.

Management of acute aortic dissection in critical care

Aortic dissections are associated with significant mortality and morbidity, with rapid treatment paramount. They are caused by a tear in the intimal lining of the aorta that extends into the media of the wall. Blood flow through this tear leads to the formation of a false passage bordered by the inner and outer layers of the media. Their diagnosis is challenging, with most deaths caused by aortic dissection diagnosed at post-mortem. Aortic dissections are classified by location and chronicity, with management strategies depending on the nature of the dissection. The Stanford method splits aortic dissections into type A and B, with type A dissections involving the ascending aorta. De Bakey classifies dissections into I, II or III depending on their origin and involvement and degree of extension. The key to diagnosis is early suspicion, appropriate imaging and rapid initiation of treatment. Treatment focuses on initial resuscitation, transfer (if possible and required) to a suitable specialist centre, strict blood pressure and heart rate control and potentially surgical intervention depending on the type and complexity of the dissection. Effective post-operative care is extremely important, with awareness of potential post-operative complications and a multi-disciplinary rehabilitation approach required. In this review article we will discuss the aetiology and classifications of aortic dissection, their diagnosis and treatment principles relevant to critical care. Critical care clinicians play a key part in all these steps, from diagnosis through to post-operative care, and thus a thorough understanding is vital.

Lactate-Based Difference as a Determinant of Outcomes following Surgery for Type A Acute Aortic Dissection: A Multi-Centre Study

Type A acute aortic dissection (TAAAD) is a serious condition within the acute aortic syndromes that demands immediate treatment. Despite advancements in diagnostic and referral pathways, the survival rate post-surgery currently sits at almost 20%. Our objective was to pinpoint clinical indicators for mortality and morbidity, particularly raised arterial lactate as a key factor for negative outcomes.

METHODS

All patients referred to the three cardiovascular centres between January 2005 and December 2022 were included in the study. The inclusion criteria required the presence of a lesion involving the ascending aorta, symptoms within 7 days of surgery, and referral for primary surgical repair of TAAAD based on recommendations, with consideration for other concomitant major cardiac surgical procedures needed during TAAAD and retrograde extension of TAAAD. We conducted an analysis of both continuous and categorical variables and utilised predictive mean matching to fill in missing numeric features. For missing binary variables, we used logistic regression to impute values. We specifically targeted early postoperative mortality and employed LASSO regression to minimise potential collinearity of over-fitting variables and variables measured from the same patient.

RESULTS

A total of 633 patients were recruited for the study, out of which 449 patients had complete preoperative arterial lactate data. The average age of the patients was 64 years, and 304 patients were male (67.6%). The crude early postoperative mortality rate was 24.5% (110 out of 449 patients). The mortality rate did not show any significant difference when comparing conservative and extensive surgeries. However, malperfusion had a significant impact on mortality [48/131 (36.6%) vs. 62/318 (19.5%), p < 0.001]. Preoperative arterial lactates were significantly elevated in patients with malperfusion. The optimal prognostic threshold of arterial lactate for predicting early postoperative mortality in our cohort was ≥2.6 mmol/L.

CONCLUSION

The arterial lactate concentration in patients referred for TAAAD is an independent factor for both operative mortality and postoperative complications. In addition to mortality, patients with an upper arterial lactate cut-off of ≥2.6 mmol/L face significant risks of VA ECMO and the need for dialysis within the first 48 h after surgery. To improve recognition and facilitate rapid transfer and surgical treatment protocol, more diligent efforts are required in the management of malperfusion in TAAAD.

Acute aortic dissection

Although substantial progress has been made in the prevention, diagnosis, and treatment of acute aortic dissection, it remains a complex cardiovascular event, with a high immediate mortality and substantial morbidity in individuals surviving the acute period. The past decade has allowed a leap forward in understanding the pathophysiology of this disease; the existing classifications have been challenged, and the scientific community moves towards a nomenclature that is likely to unify the current definitions according to morphology and function. The most important pathophysiological pathway, namely the location and extension of the initial intimal tear, which causes a disruption of the media layer of the aortic wall, together with the size of the affected aortic segments, determines whether the patient should undergo emergency surgery, an endovascular intervention, or receive optimal medical treatment. The scientific evidence for the management and follow-up of acute aortic dissection continues to evolve. This Seminar provides a clinically relevant overview of potential prevention, diagnosis, and management of acute aortic dissection, which is the most severe acute aortic syndrome.

Extended Stanford Type-A Aortic Dissection with Multivessel Coronary and Peripheral Artery Involvement: An Autopsy Case Report

We report the case of a 64-year-old male who died suddenly short after his admission to hospital because of strong chest pain and before any clinical diagnosis was established. His medical history included coronary disease with coronary by-pass surgery at the age of 40 years old, uncontrolled hypertension, diabetes mellitus, and elevated levels of cholesterol. The autopsy revealed quite a rare case of Stanford A aortic dissection with extension to the common and internal carotid arteries; the subclavian, axillary, brachial, and radial arteries; three coronary arteries; the superior mesenteric artery; and the iliac arteries. There was no histological evidence of aortitis or connective tissue disease. The death did not result from the rupture of the aortic dissection, but from myocardial ischemia due to coronary occlusion in combination with hemodynamic disturbance from stress caused by the extended aortic dissection.

The characteristics of thoracic aortic dissection in autopsy-diagnosed individuals: An autopsy study

Thoracic aortic dissection (TAD) is the most common cause of sudden cardiac death associated with aortic diseases. The age of TAD victims in forensic studies is significantly younger than hospitalized patients with TAD, while only a few studies have been conducted on autopsy-diagnosed TAD deceased. A retrospective study was conducted at the Medicolegal Center of Sun Yat-sen University from 1999 to 2019 to address the characteristics of TAD victims. A total of 200 deceased from spontaneous rupture of TAD were assessed, with 165 (82.5%) males and 175 (87.5%) Stanford type A deceased. Our main results showed that compared with patients with TAD diagnosed during their lifetime, individuals diagnosed with TAD until an autopsy showed an earlier onset (43.80 years old) and less accompanied hypertension (<50%). Sudden death was the initial symptom of 32 decedents. Instead of chest/back pain (40 decedents), abdominal pain (59 decedents) was the most common initial symptom, and 42 decedents presented with no accompanying pain. A higher proportion of abdominal pain and the painless symptom was associated with a higher risk of misdiagnosis. Women showed a more atypical clinical presentation and rapid progression than men. Younger decedents showed more pronounced left heart changes. The present study implicated the TAD individuals diagnosed until an autopsy as a particular entity, indicating the urgent need for further investigation on early diagnosis and pathogenesis of patients with TAD with atypical pain and painless or with younger age to reduce the burden of TAD-related sudden death.

Early Mortality in Type A Acute Aortic Dissection: Insights From the International Registry of Acute Aortic Dissection

Importance

Early data revealed a mortality rate of 1% to 2% per hour for type A acute aortic dissection (TAAAD) during the initial 48 hours. Despite advances in diagnostic testing and treatment, this mortality rate continues to be cited because of a lack of contemporary data characterizing early mortality and the effect of timely surgery.

Objective

To examine early mortality rates for patients with TAAAD in the contemporary era.

Design, Setting, and Participants

This cohort study examined data for patients with TAAAD in the International Registry of Acute Aortic Dissection between 1996 and 2018. Patients were grouped according to the mode of their intended treatment, surgical or medical.

Exposure

Surgical treatment.

Main Outcomes and Measures

Mortality was assessed in the initial 48 hours after hospital arrival using Kaplan-Meier curves. In-hospital complications were also evaluated.

Results

A total of 5611 patients with TAAAD were identified based on intended treatment: 5131 (91.4%) in the surgical group (3442 [67.1%] male; mean [SD] age, 60.4 [14.1] years) and 480 (8.6%) in the medical group (480 [52.5%] male; mean [SD] age, 70.9 [14.7] years). Reasons for medical management included advanced age (n = 141), comorbidities (n = 281), and patient preference (n = 81). Over the first 48 hours, the mortality for all patients in the study was 5.8%. Among patients who were medically managed, mortality was 0.5% per hour (23.7% at 48 hours). For those whose intended treatment was surgical, 48-hour mortality was 4.4%. In the surgical group, 51 patients (1%) died before the operation.

Conclusions and Relevance

In this study, the overall mortality rate for TAAAD was 5.8% at 48 hours. For patients in the medical group, TAAAD had a mortality rate of 0.5% per hour (23.7% at 48 hours). However, among those in the surgical group, 48-hour mortality decreased to 4.4%.

Relation of Community-Level Socioeconomic Status to Delayed Diagnosis of Acute Type A Aortic Dissection

Acute type A aortic dissection requires timely diagnosis and intervention. Previous studies have examined risk factors associated with delayed diagnosis; however, the effect of socioeconomic status (SES) has not been previously studied. Our study examined the impact of various SES measures on time to diagnosis. We examined time to diagnosis in consecutive cases of acute type A aortic dissection at a single institution. SES variables included race/ethnicity, Medicaid eligibility, and residence in a zip code with an increased Distressed Communities Index-an aggregate measure of community SES. Delayed diagnosis was defined as time to diagnosis in the upper quartile of the study population (>6.6 hours). A model predicting risk factors for delayed diagnosis was created using multivariable logistic regression. Our study included 124 patients with a median time to diagnosis of 3.36 hours (interquartile range [IQR] 1.83 to 6.63). A total of 92 patients were in the nondelayed cohort (median diagnosis time of 2.59 hours, IQR 1.49 to 4.18) and 32 patients were in the delayed cohort (median diagnosis time of 15.57 hours, IQR 9.34 to 28.75). In multivariable logistic regression, residence in a high-Distressed Communities Index zip code was associated with diagnostic delay (adjusted odds ratio [aOR] 5.108, p = 0.008). Patient age (aOR 0.944, p = 0.011), chest pain at presentation (aOR 0.099, p = 0.004), back pain at presentation (aOR 0.247, p = 0.012), evidence of malperfusion syndrome (aOR 0.040, p <0.001), history of hyperlipidemia (aOR 3.507, p = 0.026), and history of congestive heart failure (aOR 0.061, p = 0.036) were also significantly associated. In conclusion, our findings suggest community-level SES affects time to diagnosis in acute type A aortic dissection.

“More or less”: management of type A aortic dissections in the endovascular era

The management of type A aortic dissection presents a major therapeutic challenge in modern surgical practice. Whilst the traditional dictum, to provide timely surgical intervention with the minimum treatment needed to repair the ascending aorta as well as the primary tear, may be a reasonable strategy in older patients, a tailored approach is desired for younger patients to manage the immediate life-threatening condition, as well as for the management of lifelong complications of the residual dissected aorta. Endovascular technology continues to advance, providing an adjunctive role to open cardiac repair presently to manage downstream aortic pathology, with the aim of striving towards a complete endovascular solution for type A aortic dissections.

Incidental Finding of an Extensive Type B Aortic Dissection Extending to the Iliac Arteries

An aortic dissection is a life-threatening event that requires urgent evaluation. A dissection is defined as a tear in the innermost layer of the aortic wall forming a true and false lumen. This is normally diagnosed with a CT with contrast when clinical suspicion is present. Deciding whether urgent surgical intervention is required is key, as it may determine the survival of the patient. The treatment of type A aortic dissection involves emergent open-heart surgery. Medical treatment and clinical follow-up are recommended for uncomplicated type B dissections. In this report, we present a case of an extensive type B aortic dissection in an asymptomatic patient who required immediate surgical intervention.

Anatomy, Pathology, and Classification of Aortic Dissection

The incremental understanding of the anatomy and pathophysiology of aortic dissection over the past 250 years has predicated the modern endovascular treatments in use today. Since the early descriptions of aortic dissection, our knowledge of the predisposing factors and hemodynamic disturbances that lead to aortic dissection and overlapping syndromes, including intramural hematoma and penetrating atherosclerotic ulcer, has been fine-tuned, aided by more advanced ultrastructural histopathologic analysis and modern cross-sectional imaging techniques. However, several controversies and ambiguities of the pathophysiology and natural history of aortic dissection persist, leading to ongoing challenges in prevention, clinical diagnosis and treatment. In this review, we aim to describe the anatomy, pathology, and classification of aortic dissection and introduce the pathophysiologic basis for endovascular therapies.

Left ventricular hypertrophy and sudden cardiac death

Sudden cardiac death (SCD) is among the leading causes of death worldwide, and it remains a public health problem, as it involves young subjects. Current guideline-directed risk stratification for primary prevention is largely based on left ventricular (LV) ejection fraction (LVEF), and preventive strategies such as implantation of a cardiac defibrillator (ICD) are justified only for documented low LVEF (i.e., ≤ 35%). Unfortunately, only a small percentage of primary prevention ICDs, implanted on the basis of a low LVEF, will deliver life-saving therapies on an annual basis. On the other hand, the vast majority of patients that experience SCD have LVEF > 35%, which is clamoring for better understanding of the underlying mechanisms. It is mandatory that additional variables be considered, both independently and in combination with the EF, to improve SCD risk prediction. LV hypertrophy (LVH) is a strong independent risk factor for SCD regardless of the etiology and the severity of symptoms. Concentric and eccentric LV hypertrophy, and even earlier concentric remodeling without hypertrophy, are all associated with increased risk of SCD. In this paper, we summarize the physiology and physiopathology of LVH, review the epidemiological evidence supporting the association between LVH and SCD, briefly discuss the mechanisms linking LVH with SCD, and emphasize the need to evaluate LV geometry as a potential risk stratification tool regardless of the LVEF.

Is Compliance With Guideline Recommended Follow-Up After Aortic Dissection Associated With Survival?

BACKGROUND

Patients with acute aortic dissection (AD) remain at risk for long-term complications and thus are recommended to adhere closely to American College of Cardiology and American Heart Association aorta guideline-based follow-up imaging and clinic visits. The long-term outcomes of compliance with such a model are not well understood.

METHODS

This was a retrospective cohort study of patients at a regional AD center who survived hospital discharge for AD and who were analyzed by compliance with initial follow-up at 3 months and long term after AD. The primary end point was death.

RESULTS

A total of 172 (66% type A; 33% type B) patients survived hospitalization and were followed up over 48 months (interquartile range [IQR], 21, 88 months). Of these patients, 122 (71%) attended the first follow-up appointment, and 90 (52%) attended more than two-thirds of recommended appointments. Patients who attended the first follow-up visit had improved long-term follow-up compliance (75% [IQR, 50%, 91%]) compared with patients who did not attend the first visit (18% [IQR, 0%, 57%]). Noncompliance with the scheduled long-term follow-up was associated with a 50% increase in the risk of death (hazard ratio, 1.6; 95% confidence interval, 1.2, 2.1; P < .001). Furthermore, in patients with low compliance (consistently attending less than one-third of follow-up appointments), the lifetime risk of death after AD was more than double that of patients with high compliance (consistently attending more than two-thirds of appointments) (hazard ratio, 2.2; 95% confidence interval, 1.5, 3.1; P < .001).

CONCLUSIONS

Nearly one-third of patients with AD do not attend the first recommended follow-up visit, and such failure was associated with later noncompliance with subsequent follow-up. Low-compliant patients have double the lifetime risk of death after AD than do high-compliant patients.

Left Ventricular Concentric Geometric Patterns Are Associated With Worse Prognosis Among Patients With Type-A Aortic Dissection

Background

This study compared left ventricular (LV) characteristics between patients with type‐A and type‐B aortic dissection (AD) and evaluated the ability of LV remodeling phenotypes (hypertrophy, concentricity, or geometric patterns) to predict mortality in both AD types.

Methods and Results

We evaluated 236 patients with type A and 120 patients with type B who had echocardiograms within 60 days before or after AD diagnosis (median [25th, 75th percentiles] time difference between echocardiogram and AD diagnosis=1 [0, 6] days) from 3 centers. Patients were stratified according to LV phenotypes, and early (90‐day) and late (1‐year) mortality after AD diagnosis were assessed. In adjusted logistic regression analysis, patients with type A had higher and lower odds of concentric and eccentric hypertrophy (odds ratio [OR], 2.56; 95% CI, 1.50–4.36; P<0.001; and OR, 0.55; 95% CI, 0.31–0.97; P=0.039, respectively) than those with type B. Results of multivariable Cox‐regression analysis showed that LV remodeling phenotypes were not related to mortality in patients with type B. By contrast, LV concentricity was associated with greater early and late mortality (hazard ratio [HR], 2.22; 95% CI, 1.24–3.96; P=0.007 and HR, 2.06; 95% CI, 1.20–3.54; P=0.009, respectively) in type A. In further analysis considering normal LV geometry as reference, LV concentric remodeling and concentric hypertrophy were associated with early mortality (HR, 7.78; 95% CI, 2.35–25.78; P<0.001 and HR, 4.38; 95% CI, 1.47–13.11; P=0.008, respectively), whereas concentric remodeling was associated with late mortality (HR, 5.40; 95% CI, 1.91–15.26; P<0.001) among patients with type A. Assessment of LV geometric patterns and concentricity provided incremental prognostic value in predicting early and late mortality beyond clinical variables in patients with type A based on net reclassification improvement and integrated discrimination improvement.

Conclusions

LV geometric patterns derived from LV concentricity were associated with greater mortality among patients with type A and may be markers of adverse prognosis in this population.

Incidence and natural history of isolated abdominal aortic dissection: A population-based assessment from 1995 to 2015

BACKGROUND

Isolated abdominal dissection (IAD) is an uncommon clinical problem that is less well-understood than thoracic aortic dissection (AD). We performed a population-based assessment of the incidence, natural history, and treatment outcomes of IAD to better characterize this disease.

METHODS

We used the Rochester Epidemiology Project to identify all Olmsted County, MN residents with a diagnosis of AD, intramural hematoma or penetrating ulcer (1995-2015). Diagnostic imaging of all patients was reviewed to confirm the diagnosis of IAD for inclusion. Presentation, treatment, and outcomes were reviewed. Survival of IAD patients was compared to age- and sex-matched population controls 3:1.

RESULTS

Of 133 residents with aortic syndrome (AD, intramural hematoma, or penetrating ulcer), 23 were initially diagnosed with IAD. Nine were reclassified as having a penetrating aortic ulcer and were excluded, leaving 14 patients for review (10 male [71%]; mean age, 71 years). Three patients (21%) were symptomatic (abdominal pain, back pain, hypertension) and none had malperfusion or rupture. Prior aortic dilatation was present in eight patients (57%) and Marfan syndrome in one (7%). Two patients (14%) had iatrogenic IAD. Initial management was medical in 13 and endovascular aneurysm repair in one (symptomatic subacute, infrarenal dissection with small aneurysm). The median clinical and imaging follow-up was 6.7 years (range, 0-17 years). An abdominal aortic aneurysm occurred in eight (six at the time of IAD diagnosis, one at 2.9 years, and one at 5.2 years after diagnosis). The average growth in the entire cohort was 0.9 ± 0.4 cm, which translated to an average growth rate of 0.09 cm/year. Subsequent intervention was performed in two patients; for severe aortic stenosis with claudication in one (infrarenal aortic stenting) and increasing aortic size in one (open repair). One patient required reintervention (thrombolysis and stenting for endovascular aneurysm repair limb thrombosis). Survival for IAD at 1, 3, and 5 years was 93%, 85%, and 76%, respectively, compared with population controls at 98%, 85%, and 71%, respectively (long rank P = .38). Mortality was due to cardiovascular causes in three patients (21%) and no deaths were aortic related. Major adverse cardiac events occurred in five patients (36%) owing to heart failure.

CONCLUSIONS

IAD is rare. The initial management for asymptomatic patients is medical. The aortic growth rate is slow, with no aortic-related mortality and a low rate of aortic intervention. The overall mortality is similar to population controls. Heart failure and cardiac-related death are prevalent, suggesting that close cardiovascular care is needed in this patient population.

Chronobiological patterns of acute aortic dissection in central China

BACKGROUND

Acute aortic dissection (AAD) is a life-threatening emergency with poor clinical outcomes. Understanding the chronological patterns of AAD onset would be helpful for identifying the triggers of AAD and preventing this catastrophic event.

METHODS

We collected data from 2048 patients diagnosed with AAD at Tongji Hospital (Wuhan, China) from 2011 to 2018. The χ2 test was used to determine whether a specific period had significantly different seasonal/weekly distributions from other periods. Fourier models were used to analyse the rhythmicity in monthly/circadian distribution.

RESULTS

The mean age was 53.4±10.9 years, and 1161 patients (56.7%) were under 55 years. One thousand six hundred fifty-seven patients (80.9%) were male, and 935 cases (45.7%) were type A dissections. The proportions of patients with comorbid hypertension/diabetes were 60.3% (1234 cases) and 1.8% (36 cases), respectively. A peak was identified in colder periods (winter/December) and a trough in warmer periods (summer/June). No significant variation was observed in weekly distribution. Fourier analysis showed a statistically significant circadian variation (p<0.001) with a nocturnal trough in 2:00-3:00, a morning peak in 9:00-10:00, and an afternoon peak in 16:00-17:00. Subgroup analyses identified circadian rhythmicity in all subgroups except for the female group and younger group (younger than 55 years).

CONCLUSION

Our results confirmed that the onset of AAD exhibits significant seasonal, monthly and circadian patterns. Patients with AAD with different Stanford-type dissections, sexes, ages and hypertension statuses could present different circadian variations. These findings may provide novel perspectives for identifying the triggers of AAD and better preventing this catastrophic event.