Department of Cardiology
AZ Middelheim
Lindendreef Nr. 1
2020 Antwerp
Belgium
Tel: +32 32803255
E-mail address: ekedhi{at}yahoo.com
Department of Cardiology
AZ Middelheim
Antwerp
Belgium
We have read with great interest the data presented by Mortelmans et al.1 on the prevalence of migraine before and after closure of ASD type secundum with an Amplatzer ASD closing device. As expected, the prevalence of migraine before closure was higher in these ASD patients than in the normal population, whereas after closure, in patients who suffered from migraine before closure, migraine was clearly reduced through a reduction in its prevalence and its frequency, similar to what is seen following PFO treatment. Surprisingly, however, several de novo cases of migraine were observed after ASD closure, becoming more apparent with the bigger devices.
Re-analysing our own data in a group of patients (n:25) who underwent ASD Type II closure either by using a Starflex closing device (n:14) or by surgical closure (n:11), the observed prevalence of migraine before closure was similar to the Mortelmans' study. Also similar was the drastic reduction in prevalence, frequency, and severity of the migraine attacks after ASD closure. Unlike the Mortelmans' results, however, and regardless of ASD size, we did not see de novo cases of migraine following closure. We, therefore, suggest that the occurrence of de novo post-closure migraine in their study may perhaps not be caused by the abrupt haemodynamic change post-closure; instead, we suggest that the type of the device used could be an alternative explanation.
The Amplatzer device is composed entirely of Nitinol, an alloy of nickel, and titanium. The toxicity of the first element has been well studied and headache is a typical symptom of nickel intoxication.2,3 Because of the high nickel content of Nitinol, it is theoretically possible that nickel may dissolve from the material due to corrosion and cause unfavourable effects. Surface layers of nickeltitanium arch wires have been found to have irregular features characterized by lengthy island-like structures, from which selective dissolution of nickel may occur.4 Ni ion release was three times higher for Nitinol than for austenitic stainless steels when evaluated in physiological simulating fluids.5 It has recently been shown that allergy to nickel occurs in 12.5% (in other studies up to 20%) of a woman population who also complained of headache occurring in periodical patterns.6
As there are no sufficient data available on Nitinol biocompatibility in vivo, and no studies on the prevalence of headache after Nitinol implants, further investigation is required.
Prospective studies should evaluate the evolution of migraine after ASD Type II closure. These studies should focus on the morbidity correlated to migraine rather than on the prevalence of migraine per se. As explained earlier, the chemical components of the devices as well as their biocompatibility should be taken into consideration.
References
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