Low-flow low-gradient aortic stenosis: surgical outcomes and mid-term results after isolated aortic valve replacement

To analyse operative outcomes and mid-term results following isolated aortic valve replacement (AVR) in patients with low-flow low-gradient severe aortic stenosis (LFLG AS) compared with normal flow high-gradient aortic stenosis (NFHG AS).

A retrospective analysis of data for all isolated AVRs performed for AS at our centre in the last 17 years (n = 846). Two groups were identified: LFLG AS (n = 198, 23%) [subdivided into: True LFLG AS (n = 66, 33%) and paradoxical LFLG AS (n = 132, 67%)] and NFHG AS (n = 648, 77%). Follow-up was done by clinical visits and telephone interviews. The mean follow-up was 5.8 ± 4.2 years.

The mean age was 71.5 ± 9.7 years in the LFLG AS group and 68.7 ± 10.8 years in the NFHG group (P = 0.01). The LFLG AS group had a mean gradient 31.2 ± 7.4 mmHg compared with 59.1 ± 16.6 mmHg in the NFHG group (P = 0.001). Diabetes, chronic obstructive pulmonary disease, previous coronary disease, peripheral vascular disease, atrial fibrillation and pulmonary hypertension were significantly more frequent in the LFLG AS patients (P < 0.01). The in-hospital mortality rate was 2% in the LFLG and 1% in the NFHG group, P = 0.13. One- and 5-year mortality rates were significantly higher in the LFLG group (13 and 28 vs 4 and 16% in the NFHG, respectively, P = 0.001). Patients with true LFLG AS also had a significantly higher long-term mortality than those with paradoxical LFLG AS (27 vs 6% at 1 year and 42 vs 20% at 5 years, P < 0.05).

AVR in patients with LFLG AS is associated with similar surgical mortality but increased mid-term mortality compared with NFHG AS. Patients with true LFLG AS have the worst outcomes. Surgery should still be offered for LFLG AS on prognostic grounds and for symptomatic benefit among survivors.