  Some theories of planet formation and evolution predict that
intermediate-mass stars host more hot Jupiters than Sun-like stars, others
reach the conclusion that such objects are very rare. By determining the
frequencies of those planets we can test those theories.
  Based on the analysis of Kepler light curves it has been suggested that about
8 per cent of the intermediate-mass stars could have a close-in substellar
companion. This would indicate a very high frequency of such objects. Up to
now, there was no satisfactory proof or test of this hypothesis.
  We studied a previously reported sample of 166 planet candidates around
main-sequence A-type stars in the Kepler field. We selected six of them for
which we obtained extensive long-term radial velocity measurements with the
Alfred-Jensch 2-m telescope in Tautenburg and the Perek 2-m telescope in
Ond\v{r}ejov. We derive upper limits of the masses of the planet candidates. We
show that we are able to detect this kind of planet with our telescopes and
their instrumentation using the example of MASCARA-1 b.
  With the transit finding pipeline EXOTRANS we confirm that there is no single
transit event from a Jupiter-like planet in the light curves of those 166
stars. We furthermore determine that the upper limit for the occurrence rate of
close-in, massive planets for A-type stars in the Kepler sample is around 0.75
per cent.
  We argue that there is currently little evidence for a very high frequency of
close-in, massive planets of intermediate-mass stars.
