Subclavian steal syndrome presenting as recurrent pulmonary oedema associated with acute left ventricular diastolic dysfunction




Abstract


Subclavian steal syndrome typically presents as angina in patients with internal mammary artery grafts. Atypical clinical presentations have been rarely described. We report an unusual case of subclavian steal syndrome presenting as pulmonary oedema with acute left ventricular diastolic dysfunction and preserved ejection fraction in a patient with internal mammary artery graft and severe stenosis of the proximal left subclavian artery. After successful angioplasty and stenting of subclavian artery, the patient remained asymptomatic for six months, but then experienced acute diastolic dysfunction and recurrent pulmonary oedema associated with critical subclavian in-stent restenosis with stent deformation. This report points out that, in patients with internal mammary-to-LAD grafts, subclavian steal syndrome may present as acute left ventricular diastolic dysfunction and pulmonary oedema even in the presence of normal ejection fraction.



Introduction


The subclavian steal syndrome (SSS) is a condition that results from a stenosis of the subclavian artery proximal to the origin of the vertebral artery or the internal mammary artery . In patients with internal mammary artery grafts, the pressure drop caused by the stenosis causes the reversal of the direction of blood flow in the graft, typically leading to myocardial ischemia and anginal symptoms . Few atypical clinical presentations have been previously reported. We report an unusual case of SSS presenting as recurrent pulmonary oedema with acute left ventricular diastolic dysfunction and preserved ejection fraction in a patient with an internal mammary artery graft.





Case presentation


An 86-year old woman with history of diabetes, hypertension, previous non-Q myocardial infarction, and coronary artery bypass graft was hospitalized because of non-ST elevation acute coronary syndrome. Surgical coronary revascularization had been performed 8 years earlier because of severe progression of three-vessel coronary disease with chronic occlusion of the right coronary artery, and recurrent acute coronary syndromes despite previous percutaneous procedures at the level of main trunk bifurcation and the middle portion of the left anterior descending artery (LAD). A left internal mammary graft on the LAD and a saphenous graft on the marginal artery had been implanted, and the patient had been asymptomatic thereafter. At the current examination, clinical examination was normal, blood pressure was normal in both arms (left 140/60 mmHg, right 140/65 mmHg), the ECG showed sinus rhythm with diffuse ST depression, and echocardiography showed borderline left ventricular (LV) systolic function (ejection fraction 53%) with inferior akinesia and mild mitral regurgitation. The mitral E/A ratio was < 1, suggesting only mild diastolic impairment, whereas peak early diastolic mitral annular velocity (E’) and the E’/A’ ratio – two load-independent indexes of LV relaxation – were both normal (n.v. > 8 cm/s and > 1, respectively) ( Fig. 1 , left panel). The E/E’ ratio, an index of mean left atrial pressure that is currently recommended for non-invasive estimation of LV filling pressure , was also normal (n.v. < 8). Coronary angiography showed normal function of the grafts and confirmed chronic occlusion of the right coronary artery, but also showed critical in-stent restenosis at the level of main trunk bifurcation. A noncritical stenosis (50%) of the proximal left subclavian artery, with normal anterograde flow in the internal mammary graft, was also observed ( Fig. 2 ). Successful percutaneous revascularization of the main trunk bifurcation by kissing balloon was performed, with optimal angiographic flow restoration. On day 5 after revascularization, the patient was stable and in good general conditions. She was discharged on aspirin, clopidogrel, carvedilol, ramipril, furosemide, atorvastatin, and insulin.




Fig. 1


Tissue Doppler pattern of longitudinal mitral annulus motion (top) and standard Doppler pattern of transmitral flow (bottom) at baseline (left panel) and during acute pulmonary oedema (right panel). Despite no significant changes in LV ejection fraction, an inversion in the E’/A’ ratio and an increase in the E/E’ ratio were observed, suggesting that the pathophysiologic mechanism of pulmonary oedema was related to acute LV diastolic dysfunction.



Fig. 2


Angiography showing noncritical stenosis (thick white arrow) of the proximal left subclavian artery (LSA). LIMA = left internal mammary artery.


One week after discharge, the patient was urgently taken to the Emergency Department because of acute pulmonary oedema. The ECG only showed mild sinus tachycardia (88 bpm). Echocardiography showed no changes in either LV ejection fraction (54%) or mitral regurgitation degree, but revealed an increase in the E/A ratio, suggestive for advanced diastolic dysfunction (pseudonormal pattern), and reduced E’/A’ ratio as compared to baseline ( Fig. 1 , right panel). The E/E’ was also considerably increased, indicating raised LV filling pressures. After stabilization with oxygen and intravenous nitrates and furosemide, a significant systolic blood pressure difference (30 mmHg) was noted between the left and right arm , Doppler ultrasound showed significant stenosis of the proximal left subclavian artery (90%), a post-stenotic dilatation (11 mm), and reversal flow in the internal mammary artery with moderate impairment in the distal LAD flow. The patient was transferred to the Department of Vascular Surgery, where angiography confirmed acute progression of subclavian artery lesion ( Fig. 3 , panel A) with no changes in the coronary arteries. Percutaneous angioplasty followed by implantation of a 10 × 40 mm self-expanding nitinol stent (SMART 10 × 40 mm; Cordis Endovascular, Miami Lakes, FL) was performed, with optimal flow restoration ( Fig. 3 , panels B–D). The nitinol stent was preferred because of the tortuous anatomy of the stenotic segment. Diastolic indexes progressively returned to baseline in the following days. The patient was discharged in good condition, and careful follow-up was planned.




Fig. 3


Subclavian revascularization. Pre-procedural angiographic images (panel A) showed acute progression of subclavian stenosis (white arrow). After stent delivery (panel B, dotted arrows) and balloon inflation (panel C), an optimal flow restoration was obtained (panel D).


Six months after subclavian artery revascularization, the patient was taken to the Emergency Department because of a new episode of acute pulmonary oedema. The ECG showed sinus tachycardia, whereas echocardiography again showed a worsening of LV diastolic performance (E 125 cm/s, E’ 9 cm/s, E/E’ ratio 14) with no changes in LV ejection fraction and mitral regurgitation degree. After stabilization, coronary angiography showed unchanged findings, but a critical in-stent restenosis (80%) at the site of previous subclavian angioplasty with inverted flow in the internal mammary graft was observed ( Fig. 4 ). Another transfer to the Department of Vascular Surgery was planned to perform a new revascularization, but the patient refused any other invasive procedure.




Fig. 4


Angiographic images obtained after contrast injection in the left main coronary artery showing inverted flow in the left internal mammary artery (LIMA) (left panel), and after contrast injection in the left subclavian artery (LSA) showing in-stent restenosis (right panel, arrows).





Case presentation


An 86-year old woman with history of diabetes, hypertension, previous non-Q myocardial infarction, and coronary artery bypass graft was hospitalized because of non-ST elevation acute coronary syndrome. Surgical coronary revascularization had been performed 8 years earlier because of severe progression of three-vessel coronary disease with chronic occlusion of the right coronary artery, and recurrent acute coronary syndromes despite previous percutaneous procedures at the level of main trunk bifurcation and the middle portion of the left anterior descending artery (LAD). A left internal mammary graft on the LAD and a saphenous graft on the marginal artery had been implanted, and the patient had been asymptomatic thereafter. At the current examination, clinical examination was normal, blood pressure was normal in both arms (left 140/60 mmHg, right 140/65 mmHg), the ECG showed sinus rhythm with diffuse ST depression, and echocardiography showed borderline left ventricular (LV) systolic function (ejection fraction 53%) with inferior akinesia and mild mitral regurgitation. The mitral E/A ratio was < 1, suggesting only mild diastolic impairment, whereas peak early diastolic mitral annular velocity (E’) and the E’/A’ ratio – two load-independent indexes of LV relaxation – were both normal (n.v. > 8 cm/s and > 1, respectively) ( Fig. 1 , left panel). The E/E’ ratio, an index of mean left atrial pressure that is currently recommended for non-invasive estimation of LV filling pressure , was also normal (n.v. < 8). Coronary angiography showed normal function of the grafts and confirmed chronic occlusion of the right coronary artery, but also showed critical in-stent restenosis at the level of main trunk bifurcation. A noncritical stenosis (50%) of the proximal left subclavian artery, with normal anterograde flow in the internal mammary graft, was also observed ( Fig. 2 ). Successful percutaneous revascularization of the main trunk bifurcation by kissing balloon was performed, with optimal angiographic flow restoration. On day 5 after revascularization, the patient was stable and in good general conditions. She was discharged on aspirin, clopidogrel, carvedilol, ramipril, furosemide, atorvastatin, and insulin.


Nov 14, 2017 | Posted by in CARDIOLOGY | Comments Off on Subclavian steal syndrome presenting as recurrent pulmonary oedema associated with acute left ventricular diastolic dysfunction
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