Secondary prevention for stroke and transient ischaemic attacks

Editor—In his editorial Muir argues for the combination of perindopril and indapamide as preferred agents for lowering blood pressure after stroke or transient ischaemic attack on the basis of the perindopril protection against recurrent stroke study (PROGRESS).¹ Is this justified? PROGRESS did not compare regimens; other evidence shows that lowering blood pressure is more important than choice of drug.²

Muir says that several factors favour the PROGRESS regimen.

Firstly, the combination was well tolerated. Without making comparisons with other drugs this seems a sweeping conclusion.

Secondly, he says that dose titration of perindopril is rapid and simpler than other angiotensin converting enzyme inhibitors. This is more relevant to heart failure than hypertension.

Thirdly, he claims that perindopril may reduce blood pressure without impairing global cerebral blood flow, even in patients with moderate to severe carotid stenosis. Where is the evidence on how this compares with other drugs?

Figure 1.

Credit: ZEPHYR/SPL

The final claim (unreferenced) is that indapamide differs pharmacologically from other thiazides, with less propensity for adverse metabolic effects and some vasodilating actions. Where is robust evidence supporting this statement?

An equally valid interpretation of PROGRESS is that perindopril was an inactive component and all benefit could be attributed to indapamide.³ This fits with other studies supporting use of thiazides.⁴ The trial design allowed doctors to choose whether to use perindopril alone or combined with indapamide, confounding interpretation of this study according to agent. PROGRESS should be used to promote lowering blood pressure after a stroke or transient ischaemic attack, not to promote particular drugs or regimens.