In rural and remote communities, rapid diagnosis and referral of suspected cases of aortic dissection to an alerted cardiovascular team will provide the patient with a reasonable chance of survival.
A retired 85-year-old family physician (M.C.K.) living on the British Columbia (BC) Sunshine Coast suffered an aortic dissection. Rushed by ambulance to Sechelt Hospital, he would have died but for the quick thinking and care provided by a health care team led by a family physician, an emergency evacuation during an epic snowstorm via a Canadian Coast Guard hovercraft, and rapid surgical care by a skilled cardiac surgical team. The smooth integration of all components in the chain—diagnosis, evacuation under extraordinary conditions, complex surgery, excellent postsurgical care—led to a positive outcome. Any break in the chain could have resulted in death. The diagnosis and management of acute aortic dissection in a rural, ferry-dependent community is described, in turn, by the 3 authors. Dr Klein provides the time line.
Case
December 19, 2022, 15:40. While raking gravel, I experience searing interscapular pain and collapse.
15:48. I am incapable of calling 911. My son-in-law, Avi, calls.
15:58. BC Ambulance Service arrives at my house in Roberts Creek. The emergency medical technicians hear my description of stunning interscapular pain but are more concerned about my relatively minor “chest pain.” I insist that I’m not having a “heart attack” but a likely dissection of my aorta. Blood pressure (BP): 136/87 mm Hg.
16:16. Ambulance departs for Sechelt Hospital (about 10.5 km away).
16:28. Ambulance arrives at the hospital. The emergency medical technicians report that the “chief complaint” was “chest pain,” accompanied by transitory numbness of the right arm. They mention interscapular pain, but not that it was excruciating compared to minimal chest pain.
16:39. I am seen by Dr Adetunji Oremakinde (A.O.) who had been told that I had had a “heart attack.” Accordingly, nitroglycerin spray, acetylsalicylic acid, and hydromorphone are ordered.
16:57. Dr A.O. orders cardiac-focused laboratory studies, which include measurement of creatinine and troponin, d-dimer test, and an electrocardiogram (ECG).
Dr A.O. picks up the story:
The history I got from the ambulance team was that you (M.C.K.) developed severe, sudden-onset, sharp, tearing chest pain graded as 10 out of 10 at the onset, with associated diaphoresis, dizziness, and pallor. The ECG did not show any ST segment changes normally associated with heart attack. Your lungs were clear, and I did not see the classical signs of aortic dissection, which include bruits between the scapulae, BP and pulse discrepancy between the upper limbs, etc.
I still had a high index of suspicion that what I was dealing with might be an aortic dissection, and I did not want to wait too long before getting a computed tomography (CT) scan of your chest. Normally, I would have preferred to rule out a heart attack first,1 but I felt I could not wait for the cardiac troponin test result before proceeding. I also ordered a d-dimer test to help distinguish pulmonary embolism versus aortic dissection.2,3 You also agreed with me as a physician colleague that what you had was not a heart attack but likely an aortic dissection. I felt if I waited for the troponin or d-dimer result before making a diagnosis of aortic dissection, I would be reducing the chance of your being suitable for surgery and survival. So, I decided to do a CT scan early.
Dr Klein continues: Focus on heart attack somewhat delayed Dr A.O.’s firm diagnosis of aortic dissection. The ECG revealed only old right bundle branch block. The complete blood count test revealed hemoglobin and hematocrit levels just below the normal range, consistent with intramural blood loss into the dissection. In ambient air, my oxygen saturation level remained above 90% throughout my hospital stay.
17:09. Dr A.O. orders CT of chest and abdomen.
18:46. Normal creatinine level reported, required prior to CT to ensure safety of infusing contrast solution.
18:48. Computed tomography proceeds.
19:10. Dr A.O. sees the dissection on CT, sends it digitally to radiologist at Lion’s Gate Hospital in North Vancouver, BC, who confirms finding of “a type A thoracic aortic dissection with pericardiac effusion and extensive intramural hematoma dissecting the aorta from aortic arch to below the diaphragm. Right brachiocephalic, right common carotid, and right subclavian arteries involved. Right vertebral artery patent. Urgent thoracic/vascular surgery opinion advised.”
19:12. Dr A.O. reaches Patient Transfer Network (PTN) and requests a cardiac surgeon at Vancouver General Hospital. The Vancouver General Hospital is on diversion, so PTN contacts Dr Daniel R. Wong, cardiac surgeon at Royal Columbian Hospital (RCH) in New Westminster, south of Vancouver on the mainland.
19:40. Dr A.O. speaks with Dr Wong, who urges immediate transfer. Dr Wong advises that because of dissection, systolic BP should be kept between 90 and 110 mm Hg, titrating with labetalol and norepinephrine.
Dr Wong continues:
I was worried that you might rapidly deteriorate and might not make it to the city alive. Of particular concern, I learned that your systolic BP was dropping below 100 mm Hg. The only hope was to get surgery done that night, as otherwise you would not be likely to survive the night or be suitable for surgery if you did.
20:00. Arterial line inserted by family physician–anesthesiologist Dr Ruan van Rooyen called in from home.
20:10. Blood pressure: 81/51 mm Hg; mean arterial pressure: 90 mm Hg. Dr A.O. treats with brief norepinephrine infusion.
20:45. As the day’s last ferry to the mainland had left and helicopters cannot fly in snowstorms, Dr A.O., at several nurses’ urging, begins arranging a hovercraft evacuation. He calls the PTN, who books the transfer and hands the call to BC Emergency Health Services, who in turn calls the Joint Rescue Coordination Centre in Victoria, BC, who calls the Coast Guard hovercraft base at Sea Island near Vancouver Airport. The Joint Rescue Coordination Centre links all these components together, bringing the critical care team (CCT) to the Coast Guard Hovercraft Base.
20:45-21:41. The 2-person BC Ambulance Service CCT, led by an advanced care paramedic, arrives at the hovercraft base, joining the 5-person hovercraft crew. Because of icing, there was grave concern that the hovercraft might not be able to lift (hover), which would endanger the lives of 7 rescuers.
21:41. After de-icing, and taking de-icing solution for the return trip, the hovercraft, facing headwinds of 22 to 50 miles per hour, leaves base for Gibsons at −8°C in almost zero visibility, navigating in open ocean with only radar and GPS (Global Positioning System) signals (Figures 1 and 2).
22:17. Blood pressure: 98/57 mm Hg; mean arterial pressure: 70 mm Hg. Hydromorphone injected subcutaneously for pain. Sechelt, BC, nurses prepare me for ambulance transfer to hovercraft.
22:37. Hovercraft arrives at the Gibsons dock to be met by Gibsons & District Volunteer Fire Department, having been called by BC Ambulance Service. Firefighters are shovelling snow so the ambulance can access the hovercraft (Figure 3) and will assist with loading me onto the hovercraft (Figure 4). Based on Dr Wong’s recommendation, Dr A.O. advises the CCT to keep my systolic BP no higher than 110 mm Hg. It was between 81/57 and 90/51 mm Hg, pulse 73 beats/min; labetalol and norepinephrine stopped.
23:53. I am transferred by ambulance to the hovercraft. Hospital nurse accompanies me onboard and transfers my care to the CCT.
00:14. The hovercraft leaves Gibsons, amid snow and strong wind (Figure 5), for their base at the airport, with CCT managing my BP with intermittent doses of labetalol. The CCT told me later I was talking and taking pictures during the trip, but I have no memory of that (Figure 6).
01:13. Arrive at hovercraft base and transfer to RCH continues, with the 2 CCTs continuing their care via ambulance, driving through unplowed snowy streets.
02:14. Arrive at RCH emergency department. The surgical team has been anxiously awaiting my arrival for 4 hours. The death rate increases by about 1% to 2% per hour, or much more. Survival depends on many factors and is approximately 30%.4-8
03:15. While the operating room team is organizing, in the presence of my daughter, Naomi, Dr Wong talks with me about informed consent. (I have no memory of meeting Dr Wong.)
03:26. Taken to the operating room by original CCT.
03:27. Anesthesia starts preoperative cooling.
04:38. Dr Wong begins the operation.
Dr Wong recalls the scene:
We sped to the operating room where the team was ready and waiting. The BP required constant support with the anesthesiologist pushing pressors, so we opened rapidly to relieve the worsening tamponade. After cooling the patient down to 24.5°C with hypothermic circulatory arrest, I excised the dissected ascending aorta and replaced it with a Dacron tube. This is the standard repair for a Stanford type A acute aortic dissection.6,7 We worked fast. The cooled brain was without circulation for 7 minutes during the period of circulatory arrest, while we also perfused the brain selectively, providing antegrade cerebral perfusion. As well, I repaired the dilated aortic valve with a subcommissural annuloplasty. Although type B aortic dissections are also important to recognize, it is the aortic dissections, intramural hematomas, and other pathologies, collectively referred to as acute aortic syndrome (AAS), when they occur in a type A configuration, that are most often lethal early on.4,5
08:23. Dr Wong completes the surgery.
Canadian Coast Guard hovercraft in better weather
Canadian Coast Guard sister hovercraft, just before it left base for Gibsons
Members of Gibsons & District Volunteer Fire Department shovelling the dock for BC Ambulance Service
Canadian Coast Guard crew and Gibsons & District Volunteer Fire Department members bringing Dr Klein aboard the hovercraft
Canadian Coast Guard First Officer Alex Wu navigating the hovercraft blind in snow and wind, using only radar and GPS signals
BC Ambulance Service Advanced Care Paramedic Nathan Blackstock, caring for Dr Klein aboard the hovercraft
Differential diagnosis
Awareness of the signs and symptoms of aortic dissections and differentiation from heart attacks are essential. The frequency of AAS is low (1 to 3 cases per 100,000 population),4-8 so family doctors in rural and remote settings might never see a case. Nevertheless, without a high index of suspicion, missed diagnosis and inappropriate action are likely.9 As initially in this case, the major entity responsible for missed diagnosis is myocardial infarction.1,2 The fact that AAS is often accompanied by non-specific ST segment changes can further confuse the situation. Moreover, many other organ system symptoms can mimic AAS. Suspicion of AAS should be high when the clinician finds the following10:
sudden, tearing, cataclysmic back and chest pain, not chest pain alone, although isolated chest pain can happen in AAS,
non-specific ST segment changes on ECG,
new aortic regurgitation (due to dilated or prolapsing aortic valve),
altered state of consciousness, reduced urine output, or other end-organ dysfunction,
focal neurologic deficits,
pulse and BP differences between arms,
widened mediastinum, and
pericardial effusion.
Patients with AAS well enough to walk into the emergency department are frequently misdiagnosed.
Discussion and conclusion
Dr Klein notes:
The Canadian Coast Guard members and the CCT took considerable personal risk in my evacuation. I would not have survived without the coordinated effort of many people. While our health care system is under great strain, it is comforting that the system can work well in a serious emergency.
Up to 75% of thoracic aneurysms are degenerative, and roughly 25% are heritable, usually by autosomal dominant mode, meaning that each person with a thoracic aneurysm has a 50% chance of passing it on to their children as a genetic risk factor for aneurysms.11-13 In families unknowingly carrying the defect, sudden death of a family member might lead to the first awareness that a familial problem exists. People with thoracic aneurysms in the family should consider imaging such as CT scans along with genetic assessment and possible genetic testing to help inform management. Awareness of the usual age of onset and recommended frequency of imaging can lead to early, potentially life-saving surgical repair. Follow-up with CT or ECG at regular intervals for life, along with strict lifelong BP management, usually with β-blockers, is indicated for patients treated for AAS.14
Acknowledgment
We thank so many people involved in the case: Sechelt and Gibsons emergency medical technicians; Sechelt Hospital nursing team; Gibsons & District Volunteer Fire Department members; Canadian Coast Guard Captain Keven Naphtali, First Officer Alex Wu, and their hovercraft crew; Advanced Care Paramedic Nathan Blackstock and his partner from BC Emergency Health Services, who cared for me aboard the hovercraft; Royal Columbian Hospital cardiac ward team under Dr Brian Muth, whose nursing staff provided exemplary postoperative care; and the Sechelt community, who successfully pushed against regional authority skepticism, enabling a small rural community to obtain its own computed tomography scanner. Dr June Carroll of the University of Toronto Department of Family and Community Medicine provided genetic consultation.
Notes
Editor’s key points
▸ The authors recount a case of aortic dissection diagnosed in one of the authors, which owing to quick thinking and care provided by a health care team led by a family physician, an emergency evacuation, and rapid surgical care by a skilled cardiac surgical team, led to a positive outcome.
▸ Awareness of the signs and symptoms of aortic dissections and differentiation from heart attacks are essential. Although type B aortic dissections are important to recognize, aortic dissections, intramural hematomas, and other pathologies, collectively referred to as acute aortic syndrome (AAS), when they occur in a type A configuration, are the most lethal early on.
▸ The frequency of AAS is low (1 to 3 cases per 100,000 population), so family doctors in rural and remote settings might never see an AAS case. Nevertheless, without a high index of suspicion, missed diagnosis and inappropriate action are likely.
▸ As initially in this case, the major entity responsible for missed diagnosis is myocardial infarction.
Points de repère du rédacteur
▸ Les auteurs relatent le cas d’une dissection aortique diagnostiquée chez l’un des auteurs qui, grâce à la réaction et aux soins immédiats dispensés par une équipe de soins de santé sous la direction d’un médecin de famille, à une évacuation d’urgence et aux soins chirurgicaux rapides par une équipe de chirurgie cardiaque compétente, s’est soldée par une issue favorable.
▸ Il est essentiel d’être au fait des signes et des symptômes des dissections aortiques, et de savoir les distinguer d’un infarctus. Même s’il est important de reconnaître les dissections aortiques de type B, les dissections aortiques, les hématomes intramuraux et d’autres pathologies, collectivement désignés sous l’expression syndrome aortique aigu (SAA), lorsqu’ils se produisent dans une configuration de type A, sont les plus mortels durant la période initiale.
▸ La fréquence du SAA est faible (1 à 3 cas par 100 000 habitants), et les médecins de famille en milieu rural pourraient ne jamais voir de cas du SAA. Néanmoins, en l’absence d’un fort degré de suspicion, les diagnostics passés inaperçus et les interventions inappropriées sont probables.
▸ Initialement, comme dans le cas présent, l’infarctus du myocarde est le principal problème à la source d’un mauvais diagnostic.
Footnotes
Competing interests
None declared
This article has been peer reviewed.
Cet article a fait l’objet d’une révision par des pairs.
- Copyright © 2024 the College of Family Physicians of Canada
