Emergency TAVI in cardiogenic shock and cardiorenal syndrome secondary to severe bicuspid aortic stenosis

Abstract

A 78-year man with severe aortic stenosis awaiting elective surgical aortic valve replacement presented with worsening New York Heart Association IV shortness of breath. Despite appropriate heart failure treatment, he deteriorated and developed cardiogenic shock and cardiorenal syndrome which progressed despite inotropic support. A non-contrast-gated CT coronary angiogram was arranged in light of acute renal failure which revealed a bicuspid aortic valve. Three-dimensional transoesophageal echocardiography guidance was used to assist annulus sizing. An emergency transcatheter aortic valve replacement (eTAVI) was carried out 5 days into admission with a 34 mm Core Valve Evolut Pro valve with a no contrast technique. The patient’s blood pressure and urine output improved and no procedural complications were encountered. He was discharged after 21 days and has remained well subsequently. This case highlights the utility of eTAVI and demonstrates the feasibility of a no contrast approach.

Background

Aortic stenosis (AS) remains one of the most common valvular pathologies encountered and is associated with increased morbidity and mortality.¹ Transcatheter aortic valve replacement (TAVI) use has increased in recent years with good mortality data in patients at intermediate and high risk for surgery.^{2 3} Data presented this year has shown, with short-term follow-up, superiority of TAVI in low surgical risk patients.⁴ Improvements in technique and valve design have led to a reduction in procedural complications, indicating its implementation will continue to rise.^5–7 A paucity of randomised control trials (RCT) data exists on its use in an emergency setting in patients who are not suitable for surgery. Patients requiring inotropic support have been excluded from most RCT.

A significant proportion of patients present with, or go on to develop, cardiogenic shock due to the progressive nature of their disease. This may preclude many patients from surgical aortic valve replacement (SAVR) in the acute setting given the very high surgical risk. A recent study showed a non-significant improvement in mortality at 30 days with emergency TAVI (eTAVI) versus emergency balloon aortic valvuloplasty (eBAV) with staged TAVI, however, little data exist to guide clinicians in the management of decompensated AS with cardiogenic shock.⁸

Our case report, in agreement with other published reports on this topic, suggests eTAVI may be offered to patients with cardiogenic shock secondary to AS and highlights the need for guidance on treating this cohort.⁹ It also highlights therapeutic challenges in procedural planning in patients with renal failure, however, identifies non-contrast CT planning and transoesophageal echocardiography (TOE) guidance as a feasible option in these patients.

Case presentation

A 77-year-old man presented to the emergency department with worsening shortness of breath, weakness and fatigue on a background of severe AS awaiting elective SAVR. His background history was also notable for stage 1 prostate cancer which was under surveillance, osteoporosis, pernicious anaemia and lumbar spinal stenosis. He noticed worsening shortness of breath 7 weeks prior to admission and a declining exercise tolerance. He was under surveillance for AS for the past 12 years but became symptomatic 11 months prior to this presentation. His dyspnoea had worsened from New York Heart Association (NYHA) II at baseline to NYHA IV dyspnoea. He was feeling generally weak and had taken minimal oral intake in the days prior to admission. He attended his general practitioner 4 days prior to admission and was prescribed coamoxiclav with no improvement in symptoms for a presumed lower respiratory tract infection. He had no significant family history, drank 7 units of alcohol per week and was a non-smoker. He lived at home with his partner and was independently mobile and independent in his activities of daily living. He was due to undergo elective SAVR the same week of admission and was planning to liaise with the admissions department the following day to see if a bed was available.

He was sinus tachycardic on presentation at a rate of 105, however, his other vital signs were within normal limits. He had fine bibasal end-inspiratory crackles, an elevated jugular venous pressure (JVP), bipedal oedema to his shins and a loud ejection systolic murmur over the aortic area. Bedside echocardiographic findings were in keeping with severe low flow/low gradient AS.

An initial diagnosis of decompensated congestive cardiac failure secondary to severe AS and AI with hypervolaemic hyponatraemia was made. The patient underwent diuresis with a 40 mg bolus of intravenous furosemide with subsequent regular two times per day intravenous dosing and underwent strict fluid balance monitoring and had serial troponins and biochemistry done 4 hourly overnight.

That evening, the patient developed haemodynamically significant atrial fibrillation with a rapid ventricular rate of 140 bpm and a blood pressure (BP) of 90/60 mm Hg requiring transfer to the coronary care unit for intravenous amiodarone infusion. He was successfully chemically cardioverted back to normal sinus rhythm and had normalisation of his BP.

The following day he began to have worsening dyspnoea and orthopnea despite three doses of intravenous furosemide 40 mg and his sodium remained static at 116. He also remained clinically overloaded on examination and was commenced on a furosemide and dobutamine infusion. He was seen by the cardiothoracic team who felt he was unsuitable for SAVR in light of pulmonary oedema and hyponatraemia and recommended medical therapy with a view to re assess suitability for SAVR once stabilised. He subsequently became hypotensive and his clinical status deteriorated despite optimal medical management with furosemide infusion titrated up to 240 mg/24 hours and dobutamine to 7.5 μg/kg/hour. Further up titration in dobutamine was not tolerated due to the development of haemodynamically significant atrial fibrillation. The patient developed KDIGO III acute kidney injury (AKI) becoming oliguric 3 days into admission with an uptrend in urea and creatinine noted (figure 1). Metolazone was added to facilitate diuresis and a moderate improvement in sodium was noted to 124.

Figure 1.

Shows the patient’s CT TAVI illustrating aortic anatomy in both axial and coronal planes. TAVI, transcatheter aortic valve replacement.

Day 4 into admission, the patient deteriorated further and began to desaturate on room air. He looked increasingly tired and pale and was finding it difficult to speak. An emergency non-contrast-gated cardiac CT was arranged in light of the patients renal function to facilitate the possibility of eTAVI the following morning which revealed a type 1 L–-R bicuspid valve. An elective TAVI that was due to occur the following day had been cancelled, opening up an emergency slot. A discussion was held with the patient and his family explaining the he was no longer suitable for SAVR but TAVI in this context also carried significant risks. After deliberation the patient gave his consent to proceed with eTAVI 5 days into admission.

Investigations

The patient’s pre admission echo showed peak and mean gradients of 76/50 mm Hg, respectively, severe aortic valve calcification, an aortic valve area (AVA) of 0.63 cm² and a left ventricular ejection fraction (LVEF) of 50%. Furthermore, he had a normal coronary angiogram performed 3 months prior.

Laboratory investigations revealed the following: troponin 181 ng/L, N-terminal (NT)-pro-brain natriueretic peptide (BNP) 26 323 ng/L, sodium 116 mmol/L, serum osmolarity 248 mOsmol/Kg, urinary osmolarity 845 mOsmol/kg, urinary sodium <20 mmol/L, urea 8.6 mmol/L, haemoglobin 106 g/L, mean corpuscular volume (MCV) 93.3fl, mean corpuscular haemoglobin (MCH) 32.5 pg and C reactive protein (CRP) 12.56 mg/L. The remaining biochemistry, including thyroid function tests and cortisol, was within normal limits

A repeat echocardiogram was performed which revealed globally reduced left ventricular systolic function with an approximate LVEF of 20%, severely calcified and immobile aortic valve leaflets suggestive of a functionally bicuspid valve with severe concurrent aortic incompetence (pressure half time of 180 ms). A peak and mean gradient of 31 mmHg and 20 mmHg, respectively, and an AVA of 0.7 cm² was noted. There was moderate to severe tricuspid regurgitation and less than 50% inferior vena cava collapse.

An emergency CT coronary angiogram and thoracic aorta was performed on day 4 to delineate aortic anatomy and to facilitate valve sizing. No contrast was administered due to the patient’s worsening renal failure. Figure 1 illustrates preoperative measurement taken from the patient’s non-contrast cardiac CT showing an annulus perimeter of 76.7 mm. Non-contrast cardiac CT also demonstrates heavy calcification of the leaflets into the left ventricular tract with a suggestion of a type I L–R bicuspid valve (Sievers classification). Although image quality is enhanced with contrast, accurate ECG gating and appropriate heart control during the scan can produce adequate imaging for TAVI planning in patient with concurrent renal disease.

Figure 2 illustrates three-dimensional (3D) TOE images taken during TAVI showing an annulus perimeter of 71 mm.

Figure 2.

Illustrates intraprocedural two-dimensional transeosophageal echocardiography in the mideosophageal long and short axis aortic views. Three-dimensional images of the aortic annulus are also seen.

Diagnosis

Severe bicuspid AS with cardiogenic shock and cardiorenal syndrome.

Treatment

An eTAVI was carried out under general anaesthetic to facilitate transeosophageal echocardiogram (TOE) guidance due to severe left ventricular dysfunction and severe agitation. Right radial access was gained with a 7-French glidesheath and 0.018 cm wire was placed in the right superficial femoral artery using a long multipurpose catheter. Right femoral access was gained using a micropuncture kit and two proglides were prepared. A 14 French sheath was inserted into the right common femoral artery. Six thousand units of intravenous heparin was administered. Activated clotting time was 320 s. The valve was crossed with a straight wire and a safari wire was placed in the left ventricle. The aortic valve was predilated with a 22 mm Numed balloon (NuMed, New York, USA) and a 34 mm Core Valve Evolut Pro (Medtronic, Minneapolis, Minnesota, USA) was then deployed. The 1–2+ paravalvular leak was noted on TOE after valve deployment. The right femoral artery was closed with two proglides and a TR band was placed over the right radial artery. No contrast media was administered during the procedure and post dilatation was avoided due to severely a calcified bicuspid native aortic valve. No new left bundle branch block, atrioventricular block or PR prolongation were noted following the procedure. The patient was transferred to the cardiac care unit for monitoring after the procedure.

Outcome and follow-up

No postprocedural complications were noted and the patients BP normalised with dobutamine support post eTAVI. His post-eTAVI echo revealed an improvement in his LVEF from 20% to 30% with mild paravalvular leak. No significant procedural-related complications were encountered during the course of the admission and inotropic support was weaned on day 2 postprocedure.

Figure 3 illustrates trends in the patient’s BP, urine output (UO), creatinine and sodium over the course of the admission. He was commenced on a furosemide infusion at day 1, dobutamine at day 2 and eTAVI was performed on day 5. He underwent haemodialysis on days 7, 8 and 11. Dobutamine and furosemide infusions were weaned on day 7. Graph A illustrates systolic and diastolic BP measurements taken during admission. Normalisation of systolic BP is seen acutely post-TAVI. Graph B illustrates UO recorded over a 24-hour period. UO was down trending since admission due to cardiorenal syndrome. Further worsening in UO was noted post-TAVI due to acute tubular necrosis (ATN). The patient subsequently became polyuric 4 days post-TAVI due to resolution of the prerenal insult and ATN. Graph C illustrates creatinine trends during the admission. Creatinine levels begin to downtrend 6 days post-TAVI with concurrent haemodialysis days 7, 8 and 11 of admission. Graph D illustrates sodium levels which normalised after cardiac output improvement post-TAVI and subsequent diuresis.

Figure 3.

Demonstrates temporal changes in the patient’s blood pressure, urine output, creatinine and sodium during the course of admission.

He was discharged to his local regional hospital after a 21 day admission and underwent inpatient rehabilitation. Currently, the patient is back to his baseline function and remains at home living independently 6 months postprocedure. His discharge echo revealed an EF of 40% with a mild paravalvular leak.

Discussion

Recent epidemiological studies have reported a prevalence of AS in patients>75 years of 12.4% with 3.4% having severe AS.¹⁰ Management of decompensated AS provides a therapeutic dilemma with high mortality rates reported.¹¹ Treatment options for this cohort include SAVR, eBAV, as a definitive or bridging procedure, eTAVI and palliation. Current AHA guidance recommends TAVI in the context of prohibitive surgical risk, however, little data exist on its utilisation in the context of cardiogenic shock and this guidance is vague.¹² Major landmark trials used to guide clinical decision making in patients who have a prohibitive surgical risk, excluded patients with cardiogenic shock requiring inotropic support and patients with bicuspid aortic valves.^{2 13–15} A recent metanalysis comparing TAVI in patients with bicuspid versus tricuspid valves suggests similar mortality rates, however, little data exist on the management of patients with bicuspid AS and cardiogenic shock.¹⁶ This leaves decision making to the heart team and the patient. Furthermore, intraoperative mortality rates of up to 21% have been reported in patients with decompensated AS and cardiogenic shock who undergo SAVR usually prohibiting its use in management.¹⁷

A recent meta-analysis comparing outcomes of eTAVI vs eBAV reported mortality rates of 22.6% and 46.2%, respectively.¹⁸ Furthermore, the mean postinterventional AVA in the eBAV group was <1 cm². In the case presented, clinician discretion and patient wishes were incorporated to determine suitability for eTAVI. The patient was deemed unsuitable for SAVR by the cardiothoracic team and concurrent severe aortic regurgitation precluded eBAV as a treatment option. Although the patient and his family were aware of the significant procedural risk, given his good premorbid function and quality of life, a decision was made to proceed with TAVI as an emergency procedure.

It is important to note that, although interventional strategies for AS are planned for prior to decompensation, symptoms may rapidly progress in certain patients. This is particularly prevalent in patients with higher baseline gradients.¹⁹ One study reported that 21% of patients with AS present with an acute decompensation, with 4.5% having already been referred for SAVR.²⁰ In this case the patient had been followed up with serial echocardiography over a period of 12 years and had been asymptomatic until recently. He was referred for SAVR at the onset of symptoms but declined rapidly over this time frame. Additionally, his symptoms had been worsening for 7 weeks prior to presentation to hospital, delaying treatment.

Furthermore, the development of cardiorenal syndrome resulting in acute prerenal failure complicated procedural planning in this case. In an observational study, on the use of eTAVI in patients with cardiogenic shock, 29.6% went on to develop stage 3 AKI postprocedure with 14.8% requiring HD.²¹ No patients in this study underwent preprocedural CT planning and a 1-year survival of 59% was reported, with all-cause mortality driven by pneumonia and sepsis. A recent Society of Cardiovascular Computed Tomography (SCCT) consensus statement advises against non-contrast CT for annular sizing due shortcomings in accurately defining the annular plane.²² However, 3D TOE has been shown to produce comparable coronal and sagittal diameters to cardiac CT as well as annulus perimeter and area estimations.^{23 24}

Given the onset of oliguria preprocedurally, an exception was made to current SCCT guidance to proceed with non-contrast cardiac CT imaging with a view to facilitate annulus sizing and to confirm valvular anatomy with intraprocedural TOE guidance, which is well supported in the literature. Despite no contrast media administration the patient required HD, however, his renal function recovered prior to discharge.

Further data is needed to support TAVI in the emergency setting, however, eTAVI in this case was successful in managing a patient with severe bicuspid aortic valve stenosis and cardiogenic shock. Physicians should consider eTAVI in selected patients after in-depth discussion with the patient with regard to the significant risk associated with eTAVI. Furthermore, a minimal or no contrast exposure approach with non-contrast CT planning and TOE guidance is a feasible option in patients with deranged renal function.

Patient’s perspective.

I am grateful to the medical team for their attentive and careful assessing of their difficult options left open, and explaining with compassion, the basis of their choices to my next of kin, and openess to her comments. For about 7 weeks before my valve replacement I felt rapidly deteriorating loss of energy and severe restricting tightness and shortness of breath. After my valve replacement my breathing, and independant functioning of all my organs recovered. This was greatly supported by the daily care and encouragement of my next of kin and the medical team.

Learning points.

• Emergency transcatheter aortic valve replacement (TAVI) should be considered for patients presenting with cardiogenic shock secondary to severe aortic stenosis.

• Emergency TAVI can be considered in patients with a bicuspid aortic valve.

• Intraprocedural transoesophageal echocardiography guidance and non-contrast CT planning offer an alternative to standard practice to minimise contrast exposure in patients with renal failure.

• Patients may rapidly decline while awaiting elective surgical aortic valve replacement/TAVI. Educating patients to attend the emergency department should they become symptomatic is essential.