On 2015 May 17, Maya Guglin commented:

It is true that patients with advanced HF typically have low blood pressure. That is why almost none of them are tolerating thiazide diuretics. In fact, not a single patient from our cohort was on thiazides, so their contribution to the reported effect of LVADs can be completely excluded. Admittedly, we did not record the doses of ACE inhibitors before and after LVADs, although cardiologists are known for neglecting uptitration of HF meds after LVAD implant.

However, other publications on the same topic can shed some light on ACE doses, because I am sure some authors did record them. We summarized their findings in our recent paper "What did we learn about VADs in 2014?" published in our newborn "The VAD Journal". The text below is the excerpt from this paper.

Several reports, including ours, unanimously confirmed the discovery made by Uriel et al.in 2011: diabetes improves after LVAD. Choudhary et al. also found that fasting blood glucose improved from 136 +/- 35 to 108 +/- 29 mg/dl post-LVAD (p < 0.001), and daily insulin dose decreased from 43 +/- 37 to 29 +/- 24 units (p = 0.02). Mohamedali et al. presented similar findings and added that some patients were able to completely discontinue oral hypoglycemics. Other groups published similar findings. The nature of this phenomenon is unclear; however, Koerner et al. measured cortisol and plasma catecholamine levels and found that both decreased after the LVAD implant. (6). This may mean that reduction of the systemic inflammatory and stress response may play a role. Otherwise, improved hemodynamics in either pancreas or peripheral tissues or both may be the cause of improvement of glucose metabolism. In any case, diabetes should not be considered a contraindication to LVAD.

Uriel N, Naka Y, Colombo PC et al. Improved diabetic control in advanced heart failure patients treated with left ventricular assist devices. European journal of heart failure 2011;13:195-9.

Choudhary N, Chen L, Kotyra L, Wittlin SD, Alexis JD. Improvement in glycemic control after left ventricular assist device implantation in advanced heart failure patients with diabetes mellitus. ASAIO journal (American Society for Artificial Internal Organs : 1992) 2014;60:675-80.

Mohamedali B, Yost G, Bhat G. Mechanical circulatory support improves diabetic control in patients with advanced heart failure. European journal of heart failure 2014;16:1120-4.

Subauste AR, Esfandiari NH, Qu Y et al. Impact of left ventricular assist device on diabetes management: an evaluation through case analysis and clinical impact. Hospital practice (1995) 2014;42:116-22.

Koerner MM, El-Banayosy A, Eleuteri K et al. Neurohormonal regulation and improvement in blood glucose control: reduction of insulin requirement in patients with a nonpulsatile ventricular assist device. The heart surgery forum 2014;17:E98-102.

On 2015 May 17, David Keller commented:

Reduced diuretic doses & increased ACE-inhibitor doses account for some of the improvement in blood sugars after LVAD

Implanting a left ventricular assist device (LVAD) should reduce the doses of diuretics required to treat congestive heart failure (CHF). Thiazide diuretics are well-known to promote insulin resistance, and are often used with loop diuretics to treat CHF. Therefore, the reduced need for diuretics after LVAD implantation could account for some or all of the observed decrease in blood sugars.

Also, CHF patients often do not tolerate maximal doses of ACE-inhibitors, due to hypotension. After LVAD implantation, these patients should be able to tolerate a higher dose of ACE inhibitor, which would also have the side effect of improving insulin sensitivity.

How much of the benefit in blood sugar control in diabetic CHF patients who received LVAD implantation was due to their decreased need for diuretics (especially thiazides) and increased tolerance of ACE-inhibitors? The results of this study should be corrected for these well-known medication side-effects. Only the residual improvements in blood sugar control which are not explained by these medication effects should be attributed to improvement in the CHF itself.

On 2015 May 17, David Keller commented:

Reduced diuretic doses & increased ACE-inhibitor doses account for some of the improvement in blood sugars after LVAD

Implanting a left ventricular assist device (LVAD) should reduce the doses of diuretics required to treat congestive heart failure (CHF). Thiazide diuretics are well-known to promote insulin resistance, and are often used with loop diuretics to treat CHF. Therefore, the reduced need for diuretics after LVAD implantation could account for some or all of the observed decrease in blood sugars.

Also, CHF patients often do not tolerate maximal doses of ACE-inhibitors, due to hypotension. After LVAD implantation, these patients should be able to tolerate a higher dose of ACE inhibitor, which would also have the side effect of improving insulin sensitivity.

How much of the benefit in blood sugar control in diabetic CHF patients who received LVAD implantation was due to their decreased need for diuretics (especially thiazides) and increased tolerance of ACE-inhibitors? The results of this study should be corrected for these well-known medication side-effects. Only the residual improvements in blood sugar control which are not explained by these medication effects should be attributed to improvement in the CHF itself.

On 2015 May 17, Maya Guglin commented:

It is true that patients with advanced HF typically have low blood pressure. That is why almost none of them are tolerating thiazide diuretics. In fact, not a single patient from our cohort was on thiazides, so their contribution to the reported effect of LVADs can be completely excluded. Admittedly, we did not record the doses of ACE inhibitors before and after LVADs, although cardiologists are known for neglecting uptitration of HF meds after LVAD implant.

However, other publications on the same topic can shed some light on ACE doses, because I am sure some authors did record them. We summarized their findings in our recent paper "What did we learn about VADs in 2014?" published in our newborn "The VAD Journal". The text below is the excerpt from this paper.

Several reports, including ours, unanimously confirmed the discovery made by Uriel et al.in 2011: diabetes improves after LVAD. Choudhary et al. also found that fasting blood glucose improved from 136 +/- 35 to 108 +/- 29 mg/dl post-LVAD (p < 0.001), and daily insulin dose decreased from 43 +/- 37 to 29 +/- 24 units (p = 0.02). Mohamedali et al. presented similar findings and added that some patients were able to completely discontinue oral hypoglycemics. Other groups published similar findings. The nature of this phenomenon is unclear; however, Koerner et al. measured cortisol and plasma catecholamine levels and found that both decreased after the LVAD implant. (6). This may mean that reduction of the systemic inflammatory and stress response may play a role. Otherwise, improved hemodynamics in either pancreas or peripheral tissues or both may be the cause of improvement of glucose metabolism. In any case, diabetes should not be considered a contraindication to LVAD.

Uriel N, Naka Y, Colombo PC et al. Improved diabetic control in advanced heart failure patients treated with left ventricular assist devices. European journal of heart failure 2011;13:195-9.

Choudhary N, Chen L, Kotyra L, Wittlin SD, Alexis JD. Improvement in glycemic control after left ventricular assist device implantation in advanced heart failure patients with diabetes mellitus. ASAIO journal (American Society for Artificial Internal Organs : 1992) 2014;60:675-80.

Mohamedali B, Yost G, Bhat G. Mechanical circulatory support improves diabetic control in patients with advanced heart failure. European journal of heart failure 2014;16:1120-4.

Subauste AR, Esfandiari NH, Qu Y et al. Impact of left ventricular assist device on diabetes management: an evaluation through case analysis and clinical impact. Hospital practice (1995) 2014;42:116-22.

Koerner MM, El-Banayosy A, Eleuteri K et al. Neurohormonal regulation and improvement in blood glucose control: reduction of insulin requirement in patients with a nonpulsatile ventricular assist device. The heart surgery forum 2014;17:E98-102.