An unusual case of cardiogenic shock late following surgical aortic valve replacement

Abstract

The present case describes a rare but potentially life-threatening complication following surgical aortic valve replacement (AVR): iatrogenic coronary ostial stenosis (ICOS). The incidence of ICOS is estimated to be between 0.3% and 5% of all AVR and it generally occurs within 6 months after the procedure. In most cases, either the left main stem or the ostium of the right coronary artery (RCA) is affected, although stenosis of the ostium of the left anterior descending artery can also occur. However, to the best of our knowledge, the simultaneous involvement of both coronary ostia, presenting with rapid onset cardiogenic shock requiring inotropic support and intra-aortic balloon pump placement, has never been reported.

<Learning objective: Iatrogenic coronary ostial stenosis (ICOS) is a rare but possible complication that can occur after aortic valve replacement. When ICOS is suspected, especially in unstable patients, a prompt diagnosis and early revascularization therapy is crucial. In this clinical setting, coronary percutaneous coronary intervention appears to be the best revascularization option.>

Introduction

Acute coronary syndrome as a result of iatrogenic coronary ostial stenosis (ICOS) is a rare but potentially life-threatening complication following surgical aortic valve replacement (AVR).

The incidence of this complication, first described by Roberts and Morrow in 1967, is estimated between 0.3% and 5% of all AVR and it generally occurs within 6 months after the procedure [1].

In most cases, either the left main stem or the ostium of the right coronary artery (RCA) is affected, although stenosis of the ostium of the left anterior descending artery has also been reported [2].

To the best of our knowledge, the simultaneous involvement of both coronary ostia has been previously reported just in one case and successfully managed with emergent coronary angioplasty.

Severe anginal chest pain at rest is the most frequent manifestation, whereas less frequently patients present with exertional dyspnea, syncope or cardiogenic shock.

Case report

A 76-year-old woman with hypertension and non insulin-dependent diabetes mellitus underwent, because of effort dyspnea [New York Heart Association (NYHA) II], an echocardiogram showing a severe aortic stenosis (90 mmHg and 62 mmHg of peak and mean systolic trans-valvular gradient) with preserved left ventricular ejection fraction (LVEF). One year later, despite optimal medical therapy, the patient complained of worsening of effort dyspnea (NYHA III). Thus, after a cardiac catheterization showing normal coronary arteries (Fig. 1A and B), she was referred to surgical aortic valve replacement (AVR). The intervention was accomplished with the implantation of an aortic valve bioprosthesis (Carpentier Edwards 21 mm) which restored good functional and subjective conditions. Seven months later, the patient suffered from an episode of acute respiratory insufficiency and was hospitalized in our Intensive Care Unit. Based on X-ray chest radiogram the episode was initially interpreted as being of infectious origin, however despite tracheal intubation and antibiotic therapy a few days later the patient developed a cardiogenic shock with rapid LVEF worsening, significant desaturation, and an increase in troponin levels. Thus, it was decided to perform a coronary angiography which showed critical stenoses of both right and left main coronary ostia (Fig. 1C and D). Under intra-aortic balloon pump (IABP) assistance the patient underwent an emergent percutaneous coronary intervention (PCI). The RCA ostium was engaged with a JR4 side-holes (SH) catheter and pre-dilated with a semi-compliant 3.0 mm × 12 mm balloon after which a 3.0 mm × 8 mm everolimus eluting stent (EES) was implanted and postdilated with a non-compliant 3.5 mm × 8 mm balloon. The left main stem coronary ostium was engaged with a 3.5 EBU 6F SH guiding catheter, pre-dilated with a semi-compliant 3.5 mm × 8 mm balloon and received a 4.0 mm × 8 mm EES which was post-dilated with a semi-compliant 4.5 mm × 12 mm balloon. A final good angiographic result was accomplished (Fig. 1E and F) with stable hemodynamic conditions. This allowed extubation and removal of IABP and inotropes on day 2 after the procedure, hospital discharge on day 7, and an uneventful 6-month clinical follow-up.

Fig. 1.

Right caudal (A) and left oblique (B) angiograms showing normal coronary arteries pre-surgical aortic valve replacement (AVR). Right caudal and left oblique angiograms showing ostial left (C) and right (D) coronary stenosis 7 months after AVR. Final result after ostial everolimus-eluting stent implantation at the left (E) and right (F) coronary ostial site.

Discussion

Several patho-physiological mechanisms of ICOS have been proposed. In particular, the selective anterograde ostial cannulation for administration of the cardioplegic solution during surgery is generally thought to cause an initial mechanical vessel trauma producing immediate dissection or a chronic local vessel wall hypoxia (through compression of vasa vasorum) with a delayed anatomic narrowing of the coronary ostia by fibrous tissue formation and intimal hyperplasia [3].

Other possible causes of mechanical ostial compromise after AVR include fibrotic reaction at level of valve sutures, valve sewing ring, or at aortotomy suture line [2]. Alternatively, turbulent flow around the prosthetic valve has been advocated to possibly generate aortic root thickening, whereas an immunological reaction to the heterograft after AVR has been considered in cases of bilateral ostial coronary arteries stenosis, revealed several months following the surgical procedure.

A genetic predisposition for developing this complication has been advocated. Winckelmann et al. in their interesting study demonstrated that 70% of affected patients, as compared to 10–15% in a control group, had an epsilon 4 allele apolipoprotein E genotype that is believed to accelerate atherosclerotic disease and increase response of proliferative repair mechanisms after arterial injury [4].

From case series, the most common symptom related to ICOS is generally unstable angina, while less typically exertional dyspnea, left ventricular heart failure, ventricular arrhythmias, cardiogenic shock, or sudden death may occur.

The most peculiar aspect of our case is the relatively atypical presentation, due to the simultaneous involvement of both coronary ostia which can account for the rapid onset cardiogenic shock, requiring urgent oro-tracheal intubation, IABP implantation, and inotropic drugs administration.

In conclusion, we can affirm that when ICOS is suspected, rapid diagnosis and treatment is crucial by performing coronary angiography and prompt reperfusion. Coronary by-pass graft surgery may be considered a treatment option in case of ICOS with stable clinical presentation, however a redo surgical intervention is well known be associated with a high morbidity and mortality [5]. On the other hand, even if PCI of lesion in an aorto-ostial location is associated with higher restenosis rate with respect to non-ostial lesions [6], [7], PCI with drug-eluting stent (DES) implantation has been shown to be associated with favorable immediate and long-term clinical outcomes for the treatment of ICOS and it appears as the most reasonable revascularization option in patients with ICOS associated with cardiogenic shock [2], [8], [9].

However, further clinical evaluation of the results following DES implantation in ICOS patients is required to elucidate the long-term clinical performance of this strategy.

Conflict of interest

The authors have no conflicts of interests to declare.